when theres a trojan/virus in quarantine and you tick it at the bottom right had courner theres a box that asks restore, remove, or send t McAfee if you click remove does that remove it from you computer altogather so you have no worry over it anymore
Although just to tell you some antiviruses or programs might just totally delete the file itself. I had a problem once with Avast! when i clicked delete and it totally deleted my program run files so then i had to get it fixed... But that was with a cheesy version of xp not cheesy as in not looking good cheesy as in alot of holes. although i dont think it does it with newer versions.