The machine boots ok, I can get into BIOS ok, and the system temperatures are fine.
When I try and install windows Vista the install gets to the end of "Windows is loading files" and just restarts. No errors, nothing, just restarts.
Ive also tried installing XP, and it installs the files required, does the first reboot, then when it gets to the end of the XP splash screen (when it should start the windows desktop) it also just restarts.
Ive tried the following:
Only 1 RAM stick
Different Geforce card
IDE Drives instead of SATA
Tried installing Ubuntu
And all have the same restarting problem.
This suggests to me that the problem could be with the mobo, but wouldn't it fail to start at all? It can sit in BIOS quite happily, so that suggests to me the mobo is working ok.
Make sure you have the F3 bios version for the motherboard.
Reset the motherboard, and try the default BIOS settings. That particular board will usually detect everything by itself. If it will not boot after that, you either have faulty memory (corsair 1066 is known to work with that board so it is unlikely) or you might have an issue with the hard drive.