I just bought a new Microstar 6390 and my AGP card doesn't even fit in the slot! Looks like its backwards ... is there more than one type of AGP card form factor?

Are you sure that you're trying to insert it correctly, or that you're using the right slot? If you look at your mobo, the uppermost, almost black slot should be your AGP slot. AMR modem slots are usually that color too, but those are real tiny, and obviously won't work for a graphic card. The white slots, of whch there should be more than one, are the 32 bit PCI slots. When you insert the graphic card, it normally goes either upside down, or if there's a fan on it, with the fan toward the bottom. You also have to watch out for the front of the card (where the monitor plugs in), because that normally has to slip right in between the mobo and the case, in order for you to be able to screw it on properly afterward. Hey Intel, AMD rulez!

You probably have to force it in there (no joke) just be careful....if that makes any sense. I usually line up one corner, then put it all in.

if it is an AGP Pro slot, DO NOT force it in, they're a completely different slot

AGP Pro is supposed to be backwards compatible with regular AGP cards.