I would like to upgrade my computer as much as possible, however I'm not really sure what would be compatible or even worthwhile in getting. Here's a list of my specs, if there's anything else that would be relevant, let me know.
I have:
Pentium 4 2.8GHz processor with HT
4 512GB Sticks of ram, DDR
1 80GB Seagate hard drive (keep windows only on that)
1 200GB Maxtor hard drive (for games, music, movies, etc.)
250W PSU
Motherboard E210882
Nvidia NV36 graphics card PCI express portt(not sure on exact specs but this is the main thing I want to replace, as it's not working very well.)
Any suggestions on things I can do to make this run any better, mainly what the best video card I can get that will work with this unit would be. Thanks for the input.

AFAIK, the only NV36 in PCI-e was the PCX 5750 which is basically an FX5700 Ultra.

I'm surprised your 250W PSU is able to handle all that hardware. You may not be so lucky if/when you upgrade the video card.

How much are you willing to spend? Do you have a preference (ATI or nVidia)? Are you in the US?

Here's one possibility:

http://www.newegg.com/Product/Produ...

I'm willing to spend between 150 and 200 dollars, also I'm planning on building an entirely new system sometime this year. Preference is nvidia, and yes i'm in the US.
As for the PSU, yeah, been meaning to upgrade that for a while, but it hasn't given me any problems yet, so I've been putting it off.
Thanks for the input

if you're thinking of upgrading your GeForce make sure that your PSU is in your upgrade top list. Newer GeForce even the 8600GT requires more juice, and your 250W PSU just won't cut it. Low powered PSU also can cause damage to your parts. upgrade to at least 430W++ (80% efficiency PSU) like the CoolerMaster ExtremePower if you don't have the cash. Then you can start thinking about your GeForce upgrade.

Dip Electronic Eng
Dip Computing & IT
BSc Software Eng

Core2 Duo 6420
Gigabyte 965P-S3
2x1GB DDR667
7900GS 256DDR3 OC
2xSeagate 160GB SATA300
SB Audigy4
19" 5ms 4:3 Dell LCD

I would say at least a 500w psu now of days with modern gpu's that are sli ready which are certified for preformance gpu's.