How are you looking for the missing directory? and what did it represent?

That many video clips would on average take up around 80 to 100 gigs of space if they were just 2 minutes long. That represents to me a partition or another harddrive (as in removable storage). Maybe the files you are searching for are actually on a different drive and in your search you are finding traces of the played videos in DAT, temp files or even stored in photo applications such as editing programs.

Normally viruses and trojans don't corrupt personal data files such as videos and documents as they are there to wreck havoc on the operating system's system files and applications.

You might try a recovery program in case they were deleteted