You need to install a special type of sound card that will allow you to connect your guitar to the back. It will also allow you to plug in other stereo-type devices like keyboards or what-have-you. The most popular one is the Creative Labs Live card, because it also comes with all the software needed and is also extraordinary in games etc. I don't have one because I dont' have the $200-300 needed to buy one, but I do enjoy standing outside computer stores and looking at them. I'm sure there are other cards too. There's another alternative: a few guitars (I can't remember the brand name, it's iGuitar or something) actually have midi out in addition to the usual cable, so you can plug it into any sound card that has a midi port (most do). Hope this helped.