Thank you for the detailed instructions. I'll try them tomorrow if I
get a chance and post the results. I read a few other post that
suggested using a meter but most of them did not give anywhere as clear
instructions on how to as you have.

I was kinda hoping that I'd forgotten or didn't know about an
instillation step. I've had that happen in the past, forgot to plug
the computer in sort of errors.

I was planning to upgrade the power supply anyhow so I tried that
first.

w_tom wrote:
Try this and try that and.... well that list is long and still does
not say what is wrong. You want to identify the problem now, and then
fix it. In but minutes with a 3.5 digit multimeter, we can identify
the problem AND then replace the suspect. Do not attach or disconnect
anything. Changing things may even exponentially complicate the
problem. That 3.5 digit meter is available for less than $20 in Sears,
Lowes, K-mart, Radio Shack, and Home Depot. That's the complex part.

With computer plugged into AC receptacle, use meter to measure
voltage on purple wire between power supply and motherboard (connect
probes to purple wire by pushing into nylon connector and other probe
to chassis). That voltage must be more than 4.87 VDC. If not, power
supply controller will not tell power supply to power on. Next measure
voltage on green wire. It must be more than 2 volts before switch is
pressed and must drop immediately to less than 0.8 volts when switch is
pressed. This tells power supply to turn on.

Next measure voltage on gray wire. It must rise to more than 2.4
volts within seconds after power switch is pressed. Again, you want to
see what happens when switch is pressed - not just long after switch is
pressed. This signal tells motherboard that power supply is OK.

If gray wire is good or bad, then move on to one red, orange, and
yellow wires. Measure each as switch is pressed. Within one second,
each should exceed 3.23, 4.87, or 11.7 volts DC. If any does not rise,
then find what ever on motherboard or peripherals is excessively
loading that voltage.

Not only do numbers help you to find a the suspect. Those numbers,
if posted, mean that your replies can include useful information.
Without numbers, then every reply will be only 'try this and try that';
also called shotgunning. These numbers can also identify an
intermittent failure before that failure occurs. Useful numbers
obtained in but two minutes means a useful reply; and no shotgunning.

scenario_dave wrote:
I've tried unplugging all of the harddrives, dvd players and floppy
directly from the board. Nothing happens when I push the on switch. I
don't hear the fan start or anything. I haven't unplugged any of the
cards yet.

When you install a power supply, does anything else plug into the
motherboard besides the 20pin plug, or are there any reset switches on
the MB etc. ? My MB is about 3 years old so as far as I know I dont
need the new extra 4 pins that come with my power supply. I've
double/triple checked the 110/220 switch and the on/off switch on the
power supply. The only other thing on the power supply itself are the
plugs that plug into the MB and components.

The thing that confuses me is that I had the exact same thing happen
when I first installed the board about 3 years ago. The tech told me
that the replacement power supply that I installed was faulty and he
installed a third one and it worked. I'm wondering if there was some
other step I missed when I installed the power supply?
Since if its the power supply problem, I've bought 3 bad power supplies
in addition to the two that went bad. If its not the power supply, why
am I getting exactly the same symptoms on the same MB a second time?