Okay i know wht you are going through because i have it too, anything i plug in is unrecognised or not even shown as being plugged in...
i have tried all USB slots
i have tried installing new drivers
i have triedthe same devices on different pc's and they all work
there is still power going to the USB slots because things still charge and light up but are unusable
PLEASE HELP, THIS IS SERIOUS I CAN'T USE WEBCAM, PSP, MP3, IPOD, MEMORY STICK USB MOUSE , E.T.C
any help would be much apreciated and please help before this weekend as i need to upload some files to psp before my holiday