Fixed?
"This file is being used by another program". By intense investigation, I traced the source to mmplayer.exe, which i wanted to delete...oops, can't delete it, so i tried Unlocker...turns out that couldn't delete it either. So I got Prevx 3.0. Bad mistake, i couldnt get rid of that either, and you have to pay to use it. So I booted into safe mode, deleted prevx, but still couldnt delete mmplayer. Virus scanners didnt help, mmplayer isnt a virus. So finally i went to CCleaner, and it could delete mmplayer.
Tada!