Adding another Hard Drive
 

I am thinking of taking a Hard drive from my old system and adding it to this one what do i need to do to make this work?

you may want to check that the drive speeds (RPM) are the same, there can be slow downs if they aren't. But essentially you just have to make sure you have a place to install it (hard drive bay) and room on your motherboard for a new cable, or room on an existing cable (IDE i'm assuming) to plug it in. Most IDE cables have 3 plugs, 1 for the mobo and 2 for drives, if you were unlucky enough to have a cd drive and hard drive connected on the same IDE, then you will have to separate them, but again, not that big of a deal.