You might get a better response over in What do I Buy.

Ron

A 6670 should work, and they can be had for under $100.

Thanks for replies but I am looking for a Nvidia made card. I kinda forgot to mention that.  lol

9800 gtx is great and only cost $50 now compare to $300+ when it first came out.

4gig of RAM each slot x (times) 4= 16 gig total RAM.

Ram and PSU is one of the cheapest to upgrade.

Also in your FAN if not liquid cool, cut out a car air filter in front of your Fan to avoid dust coming inside your PC.

Hepa filter is the same as car air filter. It will not restrict any air flow, maybe a little. (2 to 5%). look at this way, a dirty dusty hardwares will overheat all your components including your CPU.

You can also fabricate a flow using soda plastic bottles where you need  air the most. make sure you use a silicone gasket maker to glue/ seal them off.

I have a total of 4 gigs. Each slot is 1 gig Ram. So you think the 9800gtx will definantly work with this system?

9800 gtx, 100 percent sure it will work in your comp. you can also upgrade to 400 series with 500 watts but not in 500 series nvidia.

always check you voltage output total. 1.5 v and so on.

What do you want to do with the system?  Are you a hardcore gamer or just enthusiast?  I would suggest the GTX550ti for about $125.  The next step would be the GTX560ti but those run about $200.  The GTX Ti models use significantly less power than most performance video cards.  Here are two good sites to use.  One is Tom's hardware with a hierarchy chart for video cards, the other is one where you can input two cards to compare performance and power usage.

www.gpureview.com/show_cards.php

 www.tomshardware.com/.../best-graphics-card-game-performance-radeon-hd-6670,2935-7.html  

FYI, the 550Ti utilizes newer technology than 9800GT and uses 52 watts less of power.

I am a game but not "hardcore" as in I am a pc idiot. I just want to upgrade from what I have and with what will work on this older system.

If your system is like most small towers it wont take a double slot card.

That limits your choices quite a bit.

A PNY  VCG98GTEE1XPB version would fit.

9800 GT EE 1024MB PCIe - PNY