We have a Dell with 768MB memory, Windows XP for home and apparently no sound card was ever installed. How do we determine what type sound card to purchase and install?
As long as the card you buy works with the operating system you have installed, then it doesn't matter. Though you may receive a lot of opinions saying the "correct" sound card is one that does *not* say "Creative" on the box.
Really, any PCI sound card should work just fine for you.
With that system, get the cheapest you can locate.
The $8 Newegg Special looks like it will work great for you [:jaydeejohn:5]