"Data Execution Prevention" - Windows Explorer

I’ve got Windows XP, and I keep getting a message saying that Data Execution Prevention needs to force Windows Explorer to quit. I figured it was a virus of some sort, but I am running Norton, ADAware, Spybot, all currently updated, and they arent helping.
Whats the deal here?

Something’s wrong with your computer. You can see here for the detailed explanation, but the short version is that in any program, some of the bits are marked as executable instructions, and some are marked as data. One of the favorite tricks of hackers is to write malicious code into the data section of a program and then force the execution of it. In order to protect against this, recent versions of Windows won’t let the bits in the data section of a program be executed.

It’s entirely possible that your copy of Windows explorer has been corrupted rather than hacked. You should try reinstalling it and see if that helps.