usb plug and play not working?

[fantasi]

hi, i have a friend whos comp cant detect usb plug and play devices e.g. mouse, keyboard, webcam. It only gets detected if he reboots his pc. Do you guys know what causes this? and how to fix?

thx

 

[fantasi]

omg forgot something,reason i ask this is because he is running win xp pro.

 

[fantasi]

ok fixed the problem. was missing a file called usb****.sys in the c:\windows\system32 folder.