Newegg finally gave me a refund, and I finally got a new video card (very quick once I got my money). A 7600 GS, couldn't quite afford a GT ($115 vs $170 - AGP versions cost a lot more than PCI Express, sadly for me). You have to plug in a molex power thing, just like my old 6600. Crossed my fingers for a minute when I plugged it in, but it works fine. So I guess it really was my old card that fizzled out.
Anyway, while it's obviously not as good as the 7600GT (basically same card, but uses cheaper video memory), so far, it seems to be noticeably faster than my 6600GT in Oblivion and The Sims 2.
So I guess I came out ahead, other than buying a new power supply I didn't need.
Very weird though - the cd that came with it, didn't have drivers that supported the card. Apparently only the most recent nvidia drivers do, from Sept, and the cd was made in July. And the box actually says the card was made in March.