Computer Reboots While Trying to Install Windows

Recently I’ve came across a blaffing problem while trying to install any version of windows. Just as the setup process is about to begin the computer will power itself down and stop working. I’ve tried every possible combination of Memory, CPU and motherboard, but nothing seems to help. I’ve also replaced the power supply, tested the hard drive for erros but it came back clean. My system is as follows: Athlon Xp 2200, MSI KV3M-V motherboard. PC2100 512MB of memory, Western Digital 40GB Hard drive and a Geforce 3 128MB 4X video card. Any ideas on how to solve this problem would be greatly appreciated. Thank you.