Passed POST but hang when loading OS

[alg7_munif]

I stumbled upon the most wierd problem in my computer life. My friend's pc is an oem pc with an oem MSI mobo. It is a 3.0GHz P4 S478 pc with 1GB (2x512)DDR ram. The problem is the PC would turn on but it will hang at the WinXP boot screen.

At first I thought that Windows has corrupted so I did a repair install from a bootable disc but it hangs at the boot screen after the system restart when the files finish loading. Then I tried formating the HDD, the computer still hangs after the reboot. So I think that it is a hardware problem. I did the test below and each time I changed anything, I did a format and tried a clean windows install but the pc would still hangs at the boot screen.

What have I did:
Clean the heatsink and applied AS5
3 pass of Memtest.
The original HDD pass the Seagate Seatools diagnostic.
Change with another HDD
I've change the Video card.
Connect the HDD to a PCI IDE controller.
Use only 1 stick of RAM in different slot.
Use a bare minimum of hardware; CPU, GPU, RAM, PSU, DVD-RW, HDD
Change the PSU with my Enermax 500W

I've also tried loading Ubuntu directly from the disc but the computer still hangs at the ubuntu loading screen. I'm already out of idea, I don't know whether the mobo is the problem or the CPU, I don't have another S478 system to try this two components.

 

[digital_exhaust]

Three passes isn't enough, and if it's hanging wile trying to boot from a live cd, I would suspect ram or a bad optical drive. Try the basics again, this time with nothing other than the mobo, cpu/hsf, one stick of ram, video card and get it to post, then add the hd, post again, and then add the optical drive, and see if you can run Ubuntu at that point... if not, pull the hd and try again. Finally, try with the other stick of ram and see what happens.

 

[alg7_munif]

Thanks for the reply, I think that the problem is caused by the mobo because I noticed that the system hangs when the fan speed is going down, probably due to a faulty Q-Fan feature or something like that but I can't disable it in BIOS because it is an OEM mobo so the BIOS has limited settings. I also noticed that some capacitors near the CPU are "expanding" at the top, I guess the the power supplied to the CPU would also be affected.

 

[digital_exhaust]

Yeah, bulging caps are never a good sign, usually a sign of impending mobo death.....