Everytime I open a program it will say " The "C:\..............." cannot be run in win32 mode. I can only open AOL & Diablo 2 for some reason. I'm a intermidiate computer user & I couldn't find what's wrong.. I tried to do a system restore but the program to do that says the same error. Please help.

Run a full anti-virus check, as well as Adaware and Spybot S&D. (update both before you run)
You have probably been hit by a virus or trojan.