During son3 morning ritual, he turns on pc, boots up fine, logs into his account fine. Gets up to grab breakfast, goes back pc is off.

Turn power off @ wall, then back on, boots up, goes to log in , pc turns off.

Again power off @ wall, back on, this process repeated several times, either you get to log into account or not.

Stuff it, I will just reformat, and it needed to doing anyway.
Reformat goes well, uninstall all the preloaded crap that was installed , dload & install, Avast Free Home, MSN, Yahoo Messenger & Firefox. Going out so turn off & continue later.

Get home & have to go through the above of turning off & back on at wall again. Unplug, take off panels, clean, check everything tight. Yep all ok.

Plug back in on & off a couple more times & finally able to log in.
Currently dloading & updating Windows.

System
XP Home ver 2002
(currently dloading & updating to Service Pack 3)

Aspire SA85 XPS MHD 12504 Intel
Celeron CPU 3.06 GHz
3.07 GHz, 224 MB of ram

So if any of the PC Nerds / Gurus have any idea what the problem could throw your thoughts this way.

Top of my list is either power supply or motherboard.

Sooner I can get on top of this the better, dont like sharing my laptop