My friend is on a Compaq Presario SR1711Nx, and he wants a new video card. He's got an AMD Sempron (P) 3400+ 2.0ghz processor, 512mb ram. I looked up his mobo, he's got a pci-e slot, and a pci slot. I'm not sure what video cards would fit, also what his power supply could handle. I don't know his power supply and neither does he. Is an upgrade on the video card possible? (Current one is integrated pos). If it is, what is the best he can upgrade to without upgrading the power supply, with power supply, and reccomendations of what to upgrade?

7600GT, if the PSU can't handle it, then I'd forget it and get a new PC altogether.

The 7600GT  should work.
He likely needs another 512mb of RAM as well.
That will limit him quite a bit as well.

7600GT would be perfect...

If it's a slim-line case you will need a low-profile card. OEM

My friend upgraded a bit, he got a new mobo, it has pci-e slots, 1gb of ram, I forget the processor, but its not duo core, 1.8-2.2ghz I forget where in there it is. I don't know his case size so I don't know if a 7600 would fit, does anyone know if it would?

Google can be your friend, took me all of 30 seconds to find. Post back with any questions.
 
http://h10025.www1.hp.com/ewfrf/wc [...] g=en&cc=us

Here you go:
 
http://www.newegg.com/Product/Prod [...] 6814130062
 
Your psu seems to have 19amps since the replacement is that:
 
http://www.power-on.com/atx12vhp300bt.html