This I can guerentee works. I had a file that I could not delete no matter what I tried. What made matters worse is that when I upgraded toa new machine, like an idiot I forgot to unselect the file when I restored the files to the new machine. You guessed it - the bad file was restored and could not be deleted. I don't even remember how I fount this tip, but it worked great.

Deleting illegal file name "lpt1"

Ok, so you've got a file called "LPT1" on your disk drive and you can't

 delete the stupid thing.

Try this:

del \\.\<drive letter>:\<directory path>\<filename>