You're typing like you have been working tirelessly on the problem.
In fact there is no user name, lol!
Okay.....relax...........just ease back, and put your hands behind your head, and close your eyes.............think about clouds floating across in the sky.
Your Power Supply is bad. Weak voltage power rail.
Don't think so? Cool.
That's what I'm here for. To teach.
Have a multimeter?
A) If ALL of the LED's were on they would use less than 1 Watt of power.
B) EACH fan uses 2 to 3 Watts of power.
C) A typical Processor can use 51 to 125 Watts of power. Just depends on what Processor it is.
(Older Intel Pentium I, II, and III, uses less than 51 Watts. Some older AMD's do also)
You press the Power On button. The plastic assembly of the Power On button in turn presses against a Power On switch,http://www.directron.com/atxswitch.html
The Power On switch is a Momentary Contact Switch.
When briefly closed the Power On switch completes a circuit.
The Soft Power On circuit.
When the Power Supply is plugged into power, there is a constant 5 Volts (DC) present.
The 5 Volt Standby power.
Pressing the Power On button redirects the 5 Volt Standby power, in the Power Supply. This 'excites' the Power Supply, and turns it on.
(Soft Power On circuit)
The first chipset (I.C.) to receive power is the BIOS chipset.
The Basic Input/Output System program is initialized.
BIOS looks to see what devices are installed, does a Ram Memory count, TURNS the Processor on, and hands the computer over to the Operating System.
(WinXP and Win7 are two examples of an O/S)
FOLLOW Anti-Static Precautions
(Yes, I know. Slightly different computer case. Principles still apply)
3) Don't think you will be hearing any BIOS Beep Codes, because there isn't enough power, lol!
For additional questions please post in a Comment.
(If Power Supply power were dynamite, your Power Supply wouldn't have enough power to bl-ow it's nose)