As much as it hurts to use Vista in the beginning (honestly, I gave up quickly and am using XP now) I'd say the easiest solution is to keep using your Vista machine if you don't want to take it to a shop. 6 years old is a pretty old machine and emachines doesn't have the best reputation. Things are bound to go wrong with the computer other than software at that age and I personally wouldn't put much money into a computer of that vintage.

Otherwise you're going to have to do some major research and education for yourself. Unless you can find a driver CD that came with your emachines computer you'll have to determine for every piece of hardware in your computer what brand and model it is. Then you'll have to use the Vista machine to get online and search for and download drivers for them. Then you'll somehow have to transfer these drivers from the Vista machine to the XP machine (probably via a CD or a USB drive depending on how your computers are configured).  Finally you'll have to install the drivers.