stuck

Hope some one can help. I down loaded a program called file zilla which is a ftp program, when I uninstalled it, it left behind a dll file that I CANT DELETE.
I keep getting a message that it may be write protected or in use. What can I do?

Try unlocker; http://www.filehippo.com/download_unlocker/

Reboot your computer, then start up in safemode, (by pressing F8 when you first click the on/off button)
Then use keyboard going to safe mode, then you can delete it there, but the easyway is use unlocker which Fabler said.
It's a lot quicker.