vista ultimate 32bit freeze on file copy to usb

Hi, I have Vista Ultimate with SP2 and updates. For some reason copying
files to or from usb drive freezes the computer. lights still on but nothing
happening. mouse pointer wont move nor any keys on keyboard. left for half
hour and still same. Used to work fine. tried different usb drives and
same problem. partitioned drive and no problem copying between partitions.
Reinstalled Vista and problem persists. Installed Windows 7 on second
partion and copys files to from usb no problems. Have HP Pavilion DV5 AMD
laptop. Dont really want to spend $500 and buy Windows 7 if can help it.
would prefer stay with vista. Also 2gb ram in machine