I've tried to everything,but it's still on my computer! When it try to delete it,in the box it reads"Cannot delete agentreg.dll:Access denied. Make sure the disk is not full or write-protected and that the file is not curently in use." All I wanted to do is scan my computer,and now I cant remove it. Thanks...

It sounds like it is still running . Have you tried shutting it down first. Usually right clcking on the icon in the system tray brings up a menu and either exit or a disable option is there. After shut down remove it from Control Panel Add/remove programs. You may need to reinstall it first if you've partly uninstalled it,

I went to the home page of the site,and uninstalled it. I uninstalled it from the add/remove panel first. But,it was still on my computer. Finally,I fully removed it. Thanks for your help though!

For anyone else reading this thread:

How to uninstall BitDefender
includes Uninstalling BitDefender using the uninstall tool