USB Port not seeing flash drive or modem

[Japster]

I have a problem with 2 of my usb ports. When I plug a flash drive or a usb modem into it, nothing happens. When I plug a usb keyboard into the port it works though. It worked fine one day and the next morning it just did not want to work anymore. Im using Windows 7, but when I use Linux, I can see the flash drive in the disk utility, but I cannot access it. Have anyone experienced something similiar?

I have not installed any new hardware or software. I even restored my backup, but the problem still persist.

[psyc]

Try one of the other ports that hasnt bin used with that device

[Japster]

The other ports is working fine with the modem or flash drive. But I want to know what is causing my ports not to work properly. I want to solve the problem

[Pada]

Japster:
Is it perhaps your front USB ports that are acting up, or is it one of the USB ports extending from the motherboard at the back of the case?

If it is the USB ports at the back of your case, then it is most likely the contact pads of the USB port that is worn out.

[Japster]

It is the back ports that extends from the motherboard. But why would my usb keyboard work pefectly on the ports. I do understand that it can be caused by the device not making contact with the pads, but when Im in linux, I can see my flash drive in the disk utility. So there is not way that this can be caused by some kind of software interference or some kind of virus?

[AstroTurf]

It is the back ports that extends from the motherboard. But why would my usb keyboard work pefectly on the ports. I do understand that it can be caused by the device not making contact with the pads, but when Im in linux, I can see my flash drive in the disk utility. So there is not way that this can be caused by some kind of software interference or some kind of virus?

lack of power to those ports?

[AstroTurf]

I had a similar problem twice now.
New PSU and it works again (seems the PSU was packing up).

[BigAl-sa]

lack of power to those ports?

+1

[Japster]

So there is no way to increase the power to these ports

[AstroTurf]

So there is no way to increase the power to these ports

Get a PSU that is not on it's way to the scrapyard.

[Japster]

well I will look into getting a new PSU then.

[Pada]

Japster:
If you have multiple HDD's + DVD drive connected to your PC at this moment, see if the ports start to work when you unplug the unnecessary devices.

[Japster]

I have disconnected my spare HHD, but that did not help at all... I can still use my other ports, but wanted to solve this problem

[sajunky]

+1 to power issue, as is the same in both Win/linux. However, don't look problems with ypur power supply pack. There are much more powerful than USB needs.
Did you try to power off computer and on again? Some motherboards have USB ports protected by overcurrent device called polyswitch. It might reset after cycling power. If doesn't, it is possible that there is permanent damage. Low current devices work, as Polystitch still allows small current to flow (even in tripped state).
Connect pendrive to one port and meassure voltage on the second one (another one which shows the same problem). There are probably fed by the same polyswitch, so voltage drop will show on the other port too.

[BigAl-sa]

On my one PC, none of the USB ports off motherboard risers worked with memory devices. Other devices worked fine. I got around this by putting a USB card into the PC.