All but 1 USB devices not recognized!

[obex_mike]

hi,

I'm running Vista Ultimate 32bit and the other day my computer stopped recognizing anything i plug into the USB ports. The strange bit is that my PreSonus FaderPort still works fine in all ports... I've tried installing, reinstalling, updating and uninstalling drivers for my MIDI keyboard (one of the things which isnt working) but can't solve the problem.

The message I get says "one of the USB devices attached... has malfunctioned and Windows does not recognize it." When I click the helpful little balloon it brings up a list of my USB ports with either Unused Port or Unknown Device with the exception of the FaderPort which is showing as USB composite device.

Nothing other than the FaderPort that i plug in is recognized - all of which have previously worked fine for ages.

The system Im using has the following:
OS - Vista Ultimate 32
Motherboard - XFX nForce 650i Ultra
Processor - Intel Core 2 Duo 2.33GHz
RAM - 2GB

I've also unistalled and reinstalled all USB devices in device manager, with no luck.

Any help would be greatly appreciated, cheers

Mike