Oh, you DID put memory in it recently?
I was going to suggest checking that, especially if you bought from Newegg, but I figured it would have been on the list of things you were putting in.
Yeah, I've had issues with memory lately. Tried to buy a pair of 2-1Gb sticks from New Egg, and one out of each malfunctioned, only reporting as 512 MB. We assembled one good set from the two, stuck the two defective ones in and sent them back, then had problems with the replacement.
I don't know if that was just that brand, Newegg, or Memory in general these days. Then again, it's also possible you accidentally stuck a stick in the wrong channel.
Just out of curiosity, does a crash on one Gmod9 server crash the other? Or do they crash independently?