Okay, so I wanna upgrade my elderly parents' web-surfing computer - a Dell Dimension 2400. It's roughly 4-5 years old. Current specs: Celeron 2.4 GHz processor (socket 478) 512 MB ram 40 GB HDD I'm well aware that for a few dollars more, I could buy a new fullsize PC, or - even better - a nettop (The Acer Aspire Revo with dual-core Atom looks sweet). However, the current setup is nearly adequate for their needs, and 75% of the motivation behind this project is my desire to tear something apart and put it back together. I've done all of the other stuff before, but my concern is the processor - I haven't ever replaced one, or done any overclocking, and don't honestly know a whole lot about that sort of thing. Let's say the voltage requirements of the new one are slightly different - i.e. 1.4 volts instead of 1.525. Is this a meaningful difference? If adjustments need to be made, are they automatic, or is it something I have to change in the BIOS or manually with a jumper or something? Also, most of the higher powered P4 processors draw more power - from 20 to 45 more watts. How do I know if the PSU is big enough? Thanks.