Computer wont power up \ boot

[uNreal]

hi, i have the following computer: Athlon64 3400+ , ABIT Kv8-pro , 1 gb kingston pc3200, ati x850xt pe l500W PSU ( dont remember the manufacturer, maybe Antec ) , artic silencer freezer 64 pro cooling.
Everything was OK until this morning, the day before i used the pc without any problems, shut it off normally, everything was ok. But in the morning i heard some strange clicking noises, the same noises the computer makes when you turn off/on the psu by fliping the back switch, the noises from the POST CODE screen. i came up and saw some strange signs/numbers showing up but i was in a hurry so i just flipped the switch of the PSU off so it wouldn't make any noise. After coming back home, i tried to power up the pc but nothing happened. I press the power button and nothing, no fans start etc. there is not POST code on the little screen, it doesnt show anything. but there is another LED that is blinking - that means that the computer is getting power from the PSU, also the monitor is on stand by so it means that it can detect the video card which also means that it is getting power... but the pc doesnt start. The only thing i actually tried was resetting the cmos, but it didnt help..

of course it can be the mobo/pc or even the psu, but i just dont understand how it could work perfectly well and then some hours later just malfunction ?

 

[SNGX1275]

About your only way to test this is to make sure everything is seated properly (power connections, graphics card, other cards). If everything is, I'd say there is a 95% chance your power supply died, hearing anything other than fan noises and hd activity from a computer is bad, popping is usually power supply.

Replace the power supply. You can also check to see if there are any obviously blown capacitors on the motherboard (the cylinder looking things - obviously blown if they are bulging or leaking goo).

Not sure what "strange signs/numbers showing up" on POST is, but that doesn't sound too good for your motherboard, unless it was just warning about voltages or fans.

 

[uNreal]

well, actually there shouldn't be any hdd/fan activity cause the computer was turned off. only the psu switch was on so by default the post display should show 00 , but it was rapidly changing the numbers and making these clicking noises, but the signs werent actually numbers, but maybe im wrong, cause as i told already, it was in the early morning and i was in a hurry

by the way, i found out that the LED that is blinking is LED1(5VSB) ...