is nobody having this problem

[fnok]

I have already asked once...it can't just be me...I ran 1.7 and had no problems....I downloaded 3 copies of one song one had different bitrate..the other 2 the same but the one had a skip in it....I want to keep the best copy...rename and delete the other 2......that sounds so easy...there is a delete button...and a rename button...when i try to delete or rename some files, it tells me i can't as the file may be in use by another application.Some files will delete..some won't.....what is the fix for this....and i have tried deleting the files directly from my hard drive...and it comes up with similar response...file may already be in use....this is a problem with 1.8...but what do i do to rectify it.
thanx