I have a very weird problem. It started suddenly after 3 8yr old boys were playing on the computer for a few hours. ( I should know better).
Anyway, I run Windows XP Home. I have Norton Internet Security 2003, updated and scans twice a week. I run Spysweeper 3.0. It is update, scans 3 times a week and watches for any unauthorized changes. I also run Spybot and Adaware. With all that "protection", I suddenly get an error message "RUNDLL32 is not a valid Win32 application" when I try to access anything in the Control Panel. I've tried to look it up on this website and in Google and I haven't found anything helpful.
I'm having another problem that I don't know if it is related. In trying to solve the above problem, I ran Spysweeper, Spybot, Norton Scan (in Safe Mode) and Adaware. Adaware would hang or freeze everytime. I uninstalled Adaware and downloaded the newest version (Adaware SE Personal). It still freezes everytime I run it even if it is running in Safe Mode. I couldn't find any good help at the Lavasoft site. Others have the problem but no resolution exists.