So, another update for ya. I took out one stick of ram (I have only two in total) and tested that one. No errors. I removed it and replaced it with the other stick. No errors. I placed both sticks back in the computer and ran another test for 6 and a half hours. No errors.
I haven't had a blue screen yet, but that's because I haven't played a game or stressed my system. I will attempt to make it blue screen later today, and post the dump file. But my question is this: why would memtest go haywire with error reports that one time, then not again after so many hours of testing? Surely if the RAM was bad, it would have reported errors during all that time, no?
Well, i'll report back as soon as I get another blue screen, and we'll see what the dump file has to say for itself.