Haha, I was afraid I was plugging in something wrong with the second card. It doesn't seem to have done any harm, at least that I can tell (I switched back to the previous monitor config and it was doing the same thing as before).

I don't exactly know what kind of monitor it is, but it could be a 12 inch. I think I have a multisync monitor with a vga adapter in the basement, I'll try that. Thanks!