Data Execution Prevention and Windows Movie Maker

Apologies if this has been asked before, but I look through a couple of threads and haven't found any satisfactory help on this problem.

Recently, my computer apprently downloaded DEP in an update, and I haven't been able to open Windows Movie Maker since. I'm nowhere near a technological genius, but I did go to advanced system properties, and it refuses to allow me to add WMM to the exception list for DEP. I can't turn DEP off either, and so far it's done nothing but hassle me, even turning off IE and Firefox once or twice.

So...if at all possible, I'm just asking for a little help, in the simplest terms, if anyone knows how to fix this. Cos for once I actually didn't cause the computer problem, and that just doesn't happen...well, until now.

So if you go to the Problem Reports and Solutions Center control panel,
click View Problem History - what data is listed for these DEP errors? That
may identify the actual culprit. =)

DEP has been there all along. The difference now is that some third party
is probably trying to do bad things with memory.