Removing power cord is necessary to clear power supply
lockout. Where is that lockout function located? On
motherboard. Does he keep buying new parts and swapping - or
locate problem in minutes with a meter?

Where is a standard computer system that requires anything
near to 425 watts. This is the nonsense I am exposing. 425
watts is the urban myth posted, in part, because too many
computer experts don't even learn basic functions in a power
supply. They even buy 300 watt supplies that have a 425 watt
label. That intentional mislabeling on 'dumped' power
supplies is proof enough that all computers require more than
400 watts.

Most every computer is just fine with a 250 watt supply. In
another post, the 400 watt supply also listed amperage for
each individual voltage. Bottom line was the 400 watt supply
really was only 300 watts. These 'dumped' supplies are quite
common where repairmen don't first collect facts - instead
just wildly speculate and shotgun a solution. The typical
computer system needs no where near 425 watts.

jeffrey wrote:
Sounds like a hardware problem. If you have to keep unplugging the
power supply directly from the wall socket, it could either be its
going bad or some part of the motherboard`s power integration system
is bad. Best thing to do is, either try using a different power
supply from another computer (if you have another to use), take the
current one out and have it tested.

OS wouldn`t have anything to do with it not wanting to power on.
Even when there is no OS on the computer, you should just get the
basic startup screen showing the memory check, video version,
choice of entering the bios setup, etc.

You could also just take both the power supply and mother board to
a computer store that can do hardware testing. Also, if you are
running a P4, I hear it is recommended to have a power supply
with at least 425 watts.

Jeff