Flavius

Check you have the following files:
in C:\Windows\inf:

usb.inf
usbccid.inf
usbcir.inf
usbport.inf
usbstor.inf
usbvideo.inf

and in C:\Windows\System32

usbmon.dll
usbperf.dll
usbui.dll

If you don't have any file you have to fill it.You can try find files copies somewhere in C:\Windows\WinSxS - to correct find use any external file manager for example Total Commander - Windows Search is not good to this,you can also extract missed files from DVD Vista.When you fill missed files in these folders,run device manager and remove all in USB controllers + restart and then system should reinstall USB controllers