It is difficult to imagine a modern computer without such a familiar USB port. Thanks to him, a mouse, keyboard, printer, and flash memory cards are so conveniently connected to a PC.
It happens that USB connectors suddenly stop working, usually this happens at the most inopportune moment. But do not rush to immediately run to the service center and give a lot of money. Perhaps the problem is at the system level and you can solve it yourself.
Now we will look at several of the most likely causes of the malfunction and how to solve them.
Sometimes it happens that having bought a new computer straight from the store, you come home, rejoice at the purchase and “use it with all your might,” but when you plug in a flash memory card or any other USB device, you find that the computer does not see them. This is a fairly common and widespread problem, you just need to connect the USB ports at the system level, through the BIOS. This is not difficult.
We go into the BIOS, look for the section “ Integrated peripherals"Or" Advanced"- depending on the BIOS version. We go in and look for the "" section, see that the value "Enabled" is in the first two points. This indicates that the inputs are connected. If not, then change the value. After the corrections, we exit the BIOS while saving the settings, restart the computer and check the operability.
It is also worth checking if the ports are connected to the motherboard, it also happens.
If the inputs on the front of the computer do not work for you, you should try connecting the device to the rear inputs, which are directly from the motherboard. If this helped, we can conclude that the front USB inputs are not working due to a lack of power, which is transmitted through the loop from the motherboard. In this case, I recommend using such ports only for flash drives, since they do not need a lot of power. And printers and other devices are better connected to the built-in outputs.
If it does not help, follow on.
The work of any part of the computer is regulated by drivers and USB is no exception.
Reboot your PC
Endless loading of a flash drive, constantly pop-up message "Device not recognized" or just no reaction to the connected device? Often, the solution to these problems is simply to restart the computer. If there are any errors or damage to the drivers, then after rebooting in automatic mode, the system will restore them to their original form.
Device manager and hardware configuration update.
It so happens that you cannot restart your computer right now due to some important process being performed. You can restore the drivers through the "Device Manager". It can be called in two ways:
1. Right-click on the "My Computer" shortcut and select "Control" from the pop-up menu;
2. Select Run from the Start menu. In the box, enter the command devmgmt.msc.
So, we have opened the Device Manager menu. We are looking for the item "USB Controllers", right-click the command "Update hardware configuration". After that, everything should work. 
Remove "USB Controller"
In our next method, we continue to work with the same menu. If a simple driver update does not help, try uninstalling and then reinstalling the same drivers.
Important! If your mouse is connected to your computer using a USB connection, then when you uninstall the drivers, it will stop working after you uninstall the corresponding driver. But don't panic! After rebooting, everything will return to normal mode.
We open the already familiar menu "Device Manager". In the "USB Controllers" section, select each device in turn, press the right bear button and click "delete". 
Here your task is to leave the mouse at the end, and remove the driver of its port as the last one. After that, we restart the computer. Standard drivers are included in the system. Therefore, after rebooting, they will reinstall themselves, this should fix the problem.
You can also manually reinstall the driver. But for this, you first need to find out which driver you need to install. This can be done using software that can show you the information you need, such as, for example, EVEREST. We look at the port model, download and install the corresponding software.
Port congestion
Each USB input is rated for a specific amperage. If your computer is under a table and for convenience you have brought the ports to the table through a USB hub, this may become causal inoperability. The fact is that the motherboard is programmed to allocate a certain amount of current to power the USB inputs. But if you made six from one input and inserted a device into each of them, then the motherboard is not able to supply the required amount of current to ensure the operability of all connected devices. Protection is triggered and power is cut off.
First, try turning off all unnecessary devices. If that doesn't work, unplug the hub and plug in the device directly without it. Before doing this, it is advisable to reboot the system.
If all of the above methods did not help to cope with the problem, you should try reinstalling the operating system. It happens that some update is released on the system, even if it is small, and it starts to conflict with the already installed drivers.
USB and Windows 10
After upgrading the PC to Windows 10, it is not uncommon in various forums to report that USB inputs are not working (and not only, to be honest). This is due to the "dampness" of the system. The farther from the release, the more all sorts of fixes came out, including to eliminate these problems. Therefore, I recommend that if such a problem occurs, first of all, check the system for updates. If it doesn't help, write to the manufacturer and wait for a solution to the problem.
If all of the above methods did not help, most likely there is a breakdown in the technical part of the computer. The most harmless of the options may be that a foreign object gets into the port, which prevents the device from connecting normally.
More serious can be damage to the controller of one of the ports or, worst of all, breakdown of the north bridge, which is responsible for the operation of USB inputs. If replacing one controller is not expensive, although it is also expensive for laptops, then replacing the south bridge will cost you a pretty penny. The option to fix it is almost impossible.
The only way out in this situation is to contact the service center.
Sometimes it happens that the operation of all ports is blocked by some one device connected to the computer. It is necessary to disconnect all devices and try to connect one at a time, while checking their work each time. It often happens that due to a faulty plug, for example, a keyboard or mouse, all ports are short-circuited or short-circuited.
Although now this is quite rare, it happens that a low-power 300V power supply is installed in the computer, for example, the problem may be hidden in it. It is worth trying to replace it with a more powerful one at least 450-500V. Either way, installing a better power supply won't interfere with your computer in any way.
In conclusion, it should be noted that problems can be both in the system and in the technical part. If it was not possible to fix the problem, from a systemic point of view, then without proper knowledge it is not worth going under the cover of a computer and laptop and trying to re-solder the sockets, it is better to leave it to trained people in service centers.
In contact with
Of the many technologies that have had a major impact on the computing world, the emergence of USB (Universal Serial Bus) is one of the most important. USB ports rarely cause any problems, but if they do appear, they are quickly resolved.
Let's consider the main problems with USB ports and methods of solving them:
USB port not working - what to do?
Any hardware device communicates with the operating system through a driver. In most cases, the problem with hardware devices is due to the installed drivers. The same goes for USB ports. Here are some software-level USB troubleshooting methods:
Just restart your computer
If the USB ports stop working, then just try restarting your computer. If there are any problems with loading the drivers, then the next time you boot your computer, they will be resolved after a restart.
Device manager update
If restarting the computer did not help, then. For Windows XP, click START -\u003e Run and at the text entry point, type devmgmt.msc... In the window that appears, right-click on the name of your computer and select Update hardware configuration.
Disconnecting the USB controller
Another way is to uninstall and then reinstall the USB device controller. To do this, run. Find USB controllers in the list that appears. Right click on these controllers and delete them all. After removing all controllers, restart your computer. After restarting the computer, the USB controllers will automatically install.
Updating the USB port driver
Another possible reason for USB ports not working is corrupted USB drivers. Find the USB drivers on the motherboard manufacturer's website and install them.
Wrong
The USB ports may be disabled in the BIOS. To enable them go to BIOS and find USB port settings. You can learn more about the settings for your motherboard using the motherboard manual that comes with your computer. Read the note about BIOS
USB technology is one of the most important of many technologies that have had a huge impact on the computing world. USB (Universal Serial Bus - "universal serial bus") - serial data transmission interface for low-speed and medium-speed devices of computer peripherals
This technology made it really easy and convenient to work with printers, scanners and external storage devices (external hard drives, USB flash drives). All actions with the installation of USB devices were reduced to a simple principle “ Plug and play". Truly mobile, devices have become precisely because of USB technology. Not only desktops and laptops are equipped with USB ports today, but also game devices, smartphones, cameras, navigators and many other devices.
Ports USB version 2.0 provide data transfer at speeds up to 480 Mbps, and the version USB 3.0 raises the maximum transfer rate to 5.0 Gbps. The USB symbol is a kind of trident drawn both on USB devices and on computer connectors.
USB technology is already well researched and has undergone many improvements, so USB ports, when used correctly, rarely cause any problems, and troubleshooting associated problems is not much of a hassle. This article will outline the basic principles for troubleshooting USB ports.
But before you start, it's worth describing basic recommendations when working with USB ports and devicesconnected to them:
- never connect devices with visible mechanical damage to USB connectors, as well as devices with external damage to the casing or with a clear burning smell.
If the USB ports on the motherboard are mechanically damaged, it is better to disconnect them from the motherboard (connectors in the front of the case) or seal them with colored tape to prevent their use. Whenever possible, such ports are best replaced in the workshop with new ones.
Try not to overload USB ports. Their current strength is strictly limited: 500 mA for USB 2.0 and 900 mA for version 3.0. Don't try to increase the number of USB ports with different USB multipliers. Modern motherboards already have up to 10 ports, which is enough for home use. It is always safer to buy an additional PCI or PCIe USB controller than to use a USB tee.
If USB ports stop working on a laptop, then work on it becomes very difficult - you do not connect a printer, scanner, or USB flash drive. And unlike a desktop computer, installing an additional USB controller is very expensive.
In many cases, when the error message “ USB device not recognized »The problem may be in the USB port. This problem is usually quite easy to solve, since it occurs mainly at the software level.
What to do if USB ports don't work?
Any hardware device interacts with the installed operating system through a special program - driver... Many problems with devices are solved with the help of drivers. The same is the case with non-working USB ports. Below are a few ways to help you troubleshoot USB ports in software.
If the USB ports suddenly stop working and the USB devices are not detected, then the easiest way to fix this sudden problem is to restart the computer. Just restart your computer... If there were no problems loading the drivers, then this problem will be eliminated after a reboot.
Updating hardware configuration in Device Manager
If restarting the computer is not desirable at the moment (for example, due to some important operation), then you can "restart" the driver without restarting the entire computer through device Manager... To launch it on the shortcut " My computer"Right-click and select the menu item" Managemente ". Or in the menu " Start"Find the program" Execute"And after starting it enter the command devmgmt.msc.
In the window that opens, left-click once on the list of devices and then click on the " Act"then point to" Update hardware configuration". See if the section “ USB controllers". If yes, then your problem is solved, USB ports should work.
Another way to get the USB ports to work is to disable and then reinstall the USB controller. To do this, you need to run again device Manager... In the list of equipment that you will see in the window that opens, find the USB controllers section. On each of the devices in this section, right-click and delete all of them. Once you have removed all controllers, just restart your computer. The controllers will be reinstalled and the USB ports will be available again. This might solve your problem.
Updating USB Controller Drivers
Another reason why the USB ports are not working is the damaged USB controller drivers. The only way out is to find the correct drivers and reinstall them. To download the appropriate driver, you need to find out the manufacturer of the USB device port (through it). Installing the correct driver should fix this problem in an instant.
Disconnecting other USB devices
Sometimes USB ports do not work due to overload when too many USB devices are connected. USB hubs sometimes do not provide enough power for the devices connected to it. The connected device can consume all the allowed power of the computer's USB controllers. If the equipment is connected to a USB hub, simply connect the device directly to a USB port on your computer.
You can also leave the device connected to the USB hub, but disconnect the other devices in the hub first. In the future, purchase a USB hub with its own power supply that will provide sufficient power to all devices connected to it.
If none of the above methods helped, then it is likely that the USB ports have been physically damaged. Either the USB controller is damaged, in particular the south bridge of the motherboard. In this case, the best you can do is have the USB controller replaced or repaired at a service center.
There are different types of problems associated with the operation of the front USB ports on a personal computer. Sometimes there is a problem when all the front ports are not functioning. In other cases, when only one does not work or works poorly. We will try to tell you about each of the situations when usb ports do not work.
Simultaneous failure of all front ports
First, it is necessary to clarify that the front ports differ from the rear ones in that they are connected to the "motherboard" through a special ribbon cable, while the latter are part of the motherboard.
The first likely reason why the USB ports on the front of your computer often do not work is if the USB port controller is disabled. It is located on the motherboard. You can enable it using the BIOS menu. You can get here by restarting your computer and pressing one of the keys. This is usually the F2 or Delete key.
In the BIOS, you will need to go to the Integrated Peripherals section. There is a USB Configuration menu. You need to find out what position the USBController is in. If the text Disabled is opposite, then the controller is not working. Switch to the Enabled position. We save the changes and restart the computer.
You can check all USB ports by going to the "Device Manager". It contains the "USB Serial Bus Controllers" section. Some of the items may be marked with a yellow exclamation mark. Why? This indicates a malfunction or poor performance of one of the ports. Detailed information can be found in the context menu invoked by right-clicking on the device name. It is worth removing all controllers in the "Manager" and then restarting the computer. Windows OS is able to restore all controllers at boot time on its own.
The Windows operating system sometimes disables one or all of the front ports specifically to conserve power. We can independently manage the power supply, so our task at this stage is to prohibit the system from doing this. We will need the Device Manager and the Universal USB Bus Controller again. Next, click on the line "USB Root Hub" with the left button. Here we go to the "Power management" menu. We remove the check mark from the "Allow shutdown to save energy" item. We do this procedure with each USB.
There is another reason why they do not work, lies in the crashes or incorrect operation of the Windows system. This most often happens if constant updates are disabled on the operating system. It is highly advisable to restore lost system files or reinstall Windows completely. Problems with the front ports arise due to incorrect OS assembly. Therefore, it is important to only use verified Windows assemblies.
What to do if only one front USB input fails
One of the possible reasons why this is happening is a bad ribbon cable connecting the front ports to the motherboard. Then the problem with the operation of one of the ports is solved by replacing this loop independently or with the help of specialists.
The malfunction can appear if we connect several devices to the front USB ports, for example, an external drive and a phone at once, or something else. There may not be enough electricity for one of them. This situation leads to both disconnection of the port and its work intermittently. This is due to the fact that the front port interface may not have an additional power supply, that is, an adapter. Sometimes we don't notice that the front USB ports are defective. Problems only arise when the main adapter is not enough for our immediate needs. And they are solved by purchasing a USB hub with an additional power source. After replacement, we get the opportunity to connect any peripheral devices.
Before you start any of the operations listed in the article to correct the shortcomings, you need to check the contacts for connecting the loop to the motherboard. A lot of problems with front USB ports can be solved this way.
