Java Problem

Whenever i open mozilla Firefox, Ad aware, or pretty much any program, i get a message saying that my Java is corrupt.
Its been happenin ever since i restarted my PC about 30 mins ago.
I can continue what i am doing, but the program is weird (EX: when browsin the web, if i go onto any message boards i have to resign in every time i visit, and on some i cant even sign in)
i ran ad aware, Mcaffe Virus, and spybot. nothing fixed it :\
i even reinstalled Firefox
if i try to uninstall, reinstall, or delete my java folder, i just get an error and cant continue
Win XP SP1. if you need anymore info ill give it.