Having trouble finding faulty component

Recently I made a post in the software thread because I came to find that my computer had frozen and I couldn't wake the monitor. I restarted and was unable to get to a Windows loading screen. I eventually was able to use an XP CD from a Dell and reinstall Windows as my own XP Pro CD wouldn't boot. I reinstalled because my Windows partition was listed as empty and unformatted while my main partition appeared fine. This did not fix the issue since after making it through setup the computer restarted as it should but would go no farther. I can only get as far as the 'Would you like to use Safe Mode or Start Windows Normally' screen. Any option results in a restart.

I believe I have tried everything hardware-wise, but hopefully I'm just overlooking something simple. First I tried to use another hard drive, which didn't work. I used a new motherboard and processor, a different video card, two different power supplies, different RAM, a different monitor, a different power strip and even the power switch from another case. All of the pieces that were not new were working the last time I checked, at most several months ago. At one point I believe that no component was the same as the original system. I unplugged everything unnecessary, such as the CD/DVD drive and the frontpanel USB and sound connectors.

I am completely baffled. How can two different systems have this problem? Do I need an exorcist? I'm seriously out of ideas.

Thanks.

 

Is this Windows XP Sp2?

 

It was before the crash, but the reinstall is from a pre SP2 disc.