Earlier today I was called to a friend's place to repair his computers, I installed avast and ad aware with latest updates, and it turned out 3 of his computers (networked) were infected with win32.QQRob-BF. I deleted all the infected files, but run and search command were missing from start menu and regedit had been disabled, so I corrected them in the registry and they appeared again. But right before I left, I found that whenever I checked the "Show hidden files and folders" in folder options and click ok/apply, nothing happened and the hidden files couldn't be seen. When I opened folder options again, the "Do not show hidden files and folders" was rechecked again. I didn't have time to look around in the registry or to download and install hijackthis. I intend to go there again tomorrow to correct this problem, so if anyone can show me how to restore the show hidden files ability, that will save me a lot of time and I will be very grateful.