Even a 13 year old can obtain relevant numbers in one minute. Then the fewer who know how hardware works can reply with definitive answers. No numbers results only hearsay and speculation.

Yes, many use shotgunning to fix computers. Replace good parts using wild speculation until something works. Maybe a solution. Or sometimes cures symptoms. Shotgunning takes longer. Does not identify the reason for that failure. Does not teach how computers actually work. And usually costs more time and more money.

Many who do not even know how to use a meter know it is "too hard". Total nonsense. Let a kid do the labor. Then useful replies come from the fewer who actually know this stuff. No numbers mean the better informed cannot reply. The informed solve it faster and the first time by using proven diagnostics tools. And not shotgunning.

OP asked for help on what centers around a power controller. One who does not know how to use a meter, who denies a meter is useful, also admits that disconnecting resulted in nothing useful. After all that disconnecting, he admits he is still confused. Of course. He also does not know what a power controller is or what it does.

Disconnecting many parts means confusion remains. Request instructions. Obtain numbers. Then obtain help from the fewer who actually know this stuff - including what a power controller does.

Obviously neither a CPU, RAM, nor surge protector determines when a computer can power on. Simplest hardware knowledge makes that obvious. But shotgunning even removes or blames irrelevant parts using wild speculation.

Power controller decides when a computer can power on. Only a meter can say what that controller is doing.

Power controller decides nothing, just tries to awake mobo from stand-by. Power controller can't do such a decision because when mobo in stand-by mode neither +12, nor +3.3, nor -12 nor +5 power lines are active, they are disconnected by PSU. Only +5-stand-by line is active. To decide could computer being powered on power controller should test all the part for possible failure if all the above voltages will be activated. Obviously it isn't in its competence.

To find which part causes fault no need to have any "meter" (BTW what "meter" is? Is it multimeter that absolutely useless in such a trouble? Or is it oscilloscope? Or something else?)
The only thing you need to answer OP's question is known-good PSU. No more. Its enough to decide which part is broken: mobo, PSU, hdd, video, RAM etc.
I doubt that OP has an oscilloscope, pci post-card, datasheets etc to diagnose it in "proper way", but its very likely he has a PSU somewhere around.

When I had problem with my mobo I took it back to fry's electronics & all they did was connect to a benchtop psu & determined that psu was obviously bad

Could you post the make and model of your psu. I agree that a faulty psu is the most likely explanation. But certain lower quality psus are known to take out other components when they blow( yeah, Bestec and emachines, I'm looking at you!!!). In short, all the responses seem to be taking a binary either/or approach when both the motherboard and psu may be blown.

Power controller does everything to power up a computer. Anyone who knew this would not be posting outright lies about a $10 tool that answers OP's questions - without doubt or maybes. Most do not know how to use a meter or even what it does. And get angry when better solutions are recommended. Dd not even knwo a CPU cannot execute (do anything) until that power controller permits it. Explains why discussions about RAM, CPU, protector, power cord, etc are completely irrelevant.

OP's symptoms center around a power controller that others did not even know exists. They are now posting denials. Even a PSU is only a slave to that power controller; makes no decisions about power up as some believe. Numbers from a digital meter (ie $5 at Harbor Freight) and knowledge from the fewer who actually know this stuff can eliminate the OP's confusion. Confusion only made worse by didactic statements that actually contradict decades of proven engineering experience.

Ask for instructions to have a useful reply in a next post. Or just start replacing / removing parts (shotgunning) until somsthing works. Ot pay at the shop to have someone do same. And learn nothing from the experience. The only three options.

@ westom
OK, I will not argue with you.
Let it be how do you imagine it.