Graphics/sound card put in a desktop computer?

i have a desktop computer which doesnt have a graphics card or sound card, how do i know which graphics or sound cards to buy. I am looking for a really good new graphics card that can play all the new games and a sound card that works fine.

Any suggestions? does it matter which graphics card i get for my desktop computer?

i also want to upgade the RAM, how do i do that?

here is the info of my comp from dxdiag.

System Manufacturer: P4M80P

System Model: AWRDACPI

BIOS: Award Modular BIOS v6.00PG

Processor: Intel(R) Pentium(R) D CPU 3.40GHz (2 CPUs)

Memory: 960MB RAM

Graphics/sound card put in a desktop computer?

Based on your description, looks as if you have a Biostar P4M800 Pro motherboard, which has a single 8x AGP slot.

If that is the case, this is probably your best bet, its not the top, but if you want a tiny increase in performance by buying the top card, its going to cost you double the price.

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

To get the best performance though, you are going to need a PCI-Express slot, which means changing the motherboard, and probably means also changing the CPU and ram, ie, pretty close to a whole new computer. Depends how much cash and time you want to spend on it.