Posted by Relic
Well, start off by going to "Start/Programs/Accessories/System Information"
and let's have a look at what you have now.
If you have an MX 400, the very LEAST you would want to upgrade to is a ti4200/4800 series, better yet, a 6600GT. A 6600GT will run you about $150 to $170, no small chunk of change.
I'm an nVidia fanboy, which I freely admit to, but the ATI 9600 series will also be a big upgrade for you, for about $100.
An ATI 9550 would work well for you, no matter what your mobo is.
Myself, I'll have the ti4200(Albatron ti4280 Medusa) I currently have running in this system right now, up for sale in maybe two weeks, as soon as my eVGA 6600GT comes in.
I'll toss it to you for $50, gimme $10 for shipping, $60 total, and it's yours.
That's provided you live in Canada or the US, across the pond will cost more. I payed $125 for it(Canadian), and I admit I have OC'ed it, it OC's very well, but it's been run at stock clocks forever, very stable card, and it hasn't been stressed.
Lemme know if you want it, and I'll give you a date when it will be available, sometime after the 16th of this month at the latest, probably before then, depending on whether I get my new vidcard shipped to me, or decide to just drive down and pick it up(100 mile trip, one way).
Later.