-Now we know a little about the case we need to look at the power supply and it functions. The power supply as mentioned before is almost universally sold with the case itself. So don't worry to much about buying one. Now do worry about it going out one day in the far future. The replacement or upgrading of the power supply is fairly common. But don't and I mean don't tinker with the interior of the supply itself. You can be ZAPPED real quick and you might be without an appendage that is much needed for other upgrades.
-The function of the power supply is pretty simple and is to cool itself and the case, convert AC to DC. This in turn is brought to the motherboard in a step down process. The power supply is thought of in watts for the most part and in a Minitower you will have 150-200 watts. Its a good idea to stay with 200-250 for this application unless you are looking at a server case which needs to be more like 250-300 watts. The main idea is to insure that future upgrades have the power they need.
