The PC does not recognize most USB keys and External hard disk drive?

[pancham]

I have a PC problem - from yesterday does not recognize most USB keys and external hard disk drive.
I tried to change more USB ports but nothing ...
The same problem I have is with two USB keys that with the external HD.

When you connect to a USB port leaves the inscription:

"One of the USB devices connected to the computer did not work properly. Windows can not recognize it ..."

Thanks for your help.

[Pageous]

Perhaps the OS has no more drivers for the USB controller, or themselves are corrupt.
Go to Device Manager and see if the USB are marked with an "!" yellow.
If you go to "properties of the device and uninstall the drivers, then restart and when XP asks you to install the new device tries to give the drivers, you should have in the CD of the mobo, or alternatively download from the site of the manufacturer.

[pancham]

No exclamation point Displayed on the device

but how can all of a sudden does not recognize the two or more keys or external HA?
As you may have corrupted the drivers at the same time?

[Pageous]

But in Device Manager is an entry on the USB ports, type "USB" or "advanced USB Controller host?