PrinceHeart said:Are you trying to open the folders that u copy from your friend's HDD ?
maybe it might be encripted
If you are trying to open your own files that were already in your PC before you copy your friend's files to your pc:
Maybe it was some kind of computer virus with it.
try booting in safe mode and try to access those folders.
If it doesn't work.
Run System Restore to a back date before the transfer of your friend's files to your PC.
Hope it helps.
peace