Boot to safe mode and try doing it, usually works. What program are you trying to delete? Make sure its not set to start at bootup.
My free version of Malwarebytes expired, so I was going to clean it out, and get a new copy of free. The new version will probably over-write the old, but once I tried to delete the file and couldn't, it sucked me in, and I had to find the answer.
I know, I know. Let it go!
Thanks John. You're always there with the life preserver to pull us poor sods out!