unable to access AVG

the problem started after i was taking some files from a teacher via my pendrive..
the contents were made shortcut by a virus..
i knew it was a virus but i still double clicked it and it popped out some error...
after that i right clicked on the SHORTCUT and clicked SCAN WITH AVG
and i could no longer see avg running anywhere..
i tried to run avg from its installed directory with administrator rights but it says "windows cannot access the specified path, device or file."
i can neither uninstall AVG nor Repair,,.. help