I'm back. Got a new MOBO... and still get the same issue. I tried disconnecting physically every single connector until leaving only 1 SATA disk as IDE and 1 DVD. (so took out USBs, etc.).

Operating System install went up to rebooting and freezed again when updating the register... since then, freezes at the first graphic of windows 7 boot. Tried swapping disks. Same freeze at first graph. (So it does not always freeze at the same point, it passed first graphic screen at least once.

I' loosing my mind. What remains? the CPU? Heeeeelp !!!