Hi. I have an older dell e-520 with the original 320 watt power supply. Because of the number of periferals and other upgrades I have on ths comp, I'd like to put in a larger power source. I'm thinking about 450 -500 watts. Since I've never done this before, I mean I can handle the installation and all , but what should I be aware of and look for when I go looking for the new power supply? Is there anything that might jeopardize the system I already have? The computer has one of those next to useless Pentium D processors. Is there anything that I need to match to the new power supply, or install with it? Thanks, any insight you can give me is greatly appreciated.