Whatup dogz.
1.) I had a .avi file that I couldn't delete (pieceofcrapfile.avi) in my download folder.
2.) I created a new .txt file (pieceofcrapfile.txt) on my desktop and wrote some crap in it. ex. "I COMMAND YOU TO DELETE!"
3.) I renamed the file that i created on my desktop from pieceofcrapfile.txt to pieceofcrapfile.avi
4.) I moved the new file to my download folder, and windows asked me if I would like to replace the existing file with the new dummy file. (CLICK YES)
5.) After I replaced the file I was able to delete the .avi file.
Good Luck

WILLGNY
H.C.P.