I have read that I need it for assembling a computer system, but I cannot find info anywhere that says what it is used for except for "heat transference" whatever that means. Yes, I am a first time builder and truely a noob. Can anyone explain to me how its used and on what?? Or send a link I can follow and read up on it? I want to do this right the first time and seriously cant afford to fry any components. I am building a simple computer for email, web browsing, watching movies and other videos and playing my mmorpg on the lowest settings. So far my build looks like this: HD- Seagate Barracuda 7200 Processor- AMD Athlon II X2 250 Regor 3.0GHz MB- BIOSTAR A770E3 AM3 AMD 770 ATX AMD in a Antec New Solution VSK2450 Black ATX Mid Tower Computer Case 450W Power Supply I just read that you should never use a built in PSU, but this isn't a generic one. I thought Antec was a reliable name. Is this a mistake as well? I know how cheap this sounds, but I am on a shoestring budget, and just need something that runs. But is upgradable as money reappears in a fun funds. Any help would be very much appreciated.Thanks.