How to Delete Back Orifice
There are three basic steps to removing Back Orifice from your computer, once you've found it.
To delete the Registry entry, right-click on the entry's name:
... and select Delete.
Now restart the computer, find the " .exe" file (or whatever its name may be) again with the Windows Explorer, and delete that in the same manner.
There is also one more optional step, and that is to find and delete BO's companion file, windll.dll, which BO always places in the System folder. It does no harm to leave this file in place, except that some anti-BO programs will alert on its presence and assume BO may be present in your machine.