You have 3 different options.
1) a regular PCI card. A very bad idea, the technology is ancient and your onboard will probably outperform it anyway.
2) PCI-Express X16. It is the longer *probably black* slot with the little clip on the end of it. Its the most widely used. Anything from Nvidia 8000 series or better uses it (most 7000 series too). ATI started using it with x###. Then they ditched the x part of the number and stuck an HD on the end of it.
3) PCI-E 2.0 Same interface, just faster i think.
Basically, long story short as long as you DON'T buy an AGP card, you can use it. One thing to note though is you need to make sure if the card needs its own power supply plug, you have the correct one. Mine uses the standard 4 pin molex that all PSUs have had probably since the dawn of time. Most use a 6 pin PCI-e plug, some use 8 pin, Some use none at all, just look at the pictures of the card carefully before you buy it to see if you need an adapter or a new power supply.
This is going to be a very long list but here's what my favorite internet seller has for your slot.http://www.newegg.com/Product/ProductList....alue=696%3A9641
****The following only matters if you are a gamer, or someone who would like to save money****
One more thing to note, Nvidia(GeForce) used to break down their series numbers nicely. The first digit in the 4 digit series number is what series it is, 4xxx - 9xxx, higher the newer. The second digit tells you what the card is for. x0xx-x5xx is general purpose, surfing, chatting, office whatever. x6xx is the budget gamer card. x8xx is the high end gamer card. Which for all intents and purposes means that the 8800 will run your games better than a 9300, even though the 9300 is newer.
Hope I answered at least some of your questions, if you have any more post back.
Edited by smurfgod, 22 September 2008 - 05:34 AM.