Alright, here's some advice...
Get virus scan. NOW!
Then, if it's not a virus, try the following...
First, the Secure Shredder in Spybot Search & Destroy.
If that won't do it, go to the command prompt, get to the correct directory, and type "del filename" (minus the quotes).
If the file name is insanely long, move all MPG files from the folder to another one, get the command prompt to the right directory, and type the following.
del *.MPG (that's "del" then a space, then the asterisk, then .MPG. then hit enter. Then type dir/p, and see if the file is still there. If that won't do it,
try this. Go to start menu, then my computer, right click your hard drive, hit properties, then to to tools, and try "Error Checking". If none of those work,
then I dunno what to do....