Motherboard/PSU not seeing the power switch

I post this on the Motherboards forum too.

I didn't notice the PSU forum.

So I am reposting it here.

Thanks, JimF

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I put together the following:
Opteron 242 Processor
Kingston 256mb RAM
ATI 128Rage Pro Video card
Standard PS/2 Keybaord
Seagate 80mb SATA hard drive
Enermax 465 Watt PC ATX power supply

Put everything together.
Powered up.
All seemed good.
Power down.

Can't power up again until the motherboad is completely powered down. (Green LED light goes off.)

I have NO explanation.

Actually built three system with identical parts, ALL THREE work the same.

I went into the BIOS and tried, I think, ALL of the combinations there.

No change.

Initially I thought that it was a BIOS problem on the motherboard, but since I have tried large numbers of setting combinations to no avail that doesn't matter.

It doesn't matter whether the OS boots, or not.
It doesn't matter whether hard drives are attached or not.

Lastly, I tried a different power supply, (just a no name one that was already in a case.) THAT WORKS!

The two enermax power supplies I have are:
Model EG365P-VE
Model EG463P-VE

So I guess my question is now,

Has anyone else ran into this problem?
Is there a way around it?
Is there something that I missed?

I have been using Enermax before, and I have always liked them.

Maybe I should search for another brand?

Thank you for pointing out the most obvious answer. (Albiet, that was actually in the post itself.....)

There are three identical systems involved.
So there are three power supplies.
There are three cpus.
There are three sticks of memory.
There are three video cards.
etc.....

All three are having the same problem.

I find it hard to believe that three brand new power supplies are having identical problems, but it could be.

My actual questions were as follows:

Has anyone else ran into this problem?
Is there a way around it?
Is there something that I missed?

I have been using Enermax before, and I have
always liked them.

Maybe I should search for another brand?