Just a thought here... I prefer internal PCI/PCI-express sound cards but if you're at all apprehensive about performing this installation then you may want to consider a USB-attached (also known as external) sound card.
Perhaps something like this is more appealing than ripping the computer apart?
http://us.store.creative.com/Sound-Blaster-XFi-Go-Pro/M/B0044DEDC0.htm
I'm not saying that you need a Creative Sound Blaster XFi but you'll get the idea.
Good luck! :-)