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#11
1) If it's $24, don't get it. It's also on eBay, so don't get it. And no, you need AGP or PCI, not PCIE. It's also a bad gaming card.
2) It would work better (not in your computer, for the same reason as above), but it's still not a good card.
3)Video cards come use different slots. A video card should work if you buy it new. If you but one used (not reccomended), it is more likely to not work than to work well. Also, an AGP card will not fit in a PCI, PCIE, or a PCIEx16 slot.
All in all, go with the Radeon 3850. It's AGP, and it is better than the two nVidia cards that you suggested.
Also suggested, upgrade your RAM. 7 must hog a lot of it if you only have 512MB. Bump that up to a GB (no more than 2GB, as your computer does not support it). Your computer uses DDR RAM, so make sure you don't buy DDR2/3. I really don't like that processor. If you can, try to get a newer one that runs on Socket 754 (preferably a dual-core processor). Your hard drive seems fine. DVD drive is good. Sound is good.
Looks like your set. If you take my advice, than your computer will run Windows 7 really well.