Strange boot problem

[andreh]

I have a problem booting my machine which drives me absolutely crazy. Basically, since four weeks, after I press the power button, the machine boots for around 3 to four seconds. Than it switches off. Now comes the strange bit. If I press and hold the power button for 5 to 6 seconds and than press the button 3 to 4 times in sucsession the machine boots again and switches off after a short while (5-6 sec). I have to follow this procedure for around 10min to boot up completely.

What I have tried so far:
- reset BIOS
- reset all RAM and cards

This is a really anoying problem can someone please help me!

[Valtelino]

Also possibly a flaky PSU on the way out

[Tazzin]

Welcome to TechIMO!!

There are a whole lot of things that can cause issues like that:
PSU going out like Valtelino mentioned.
Could be the switch.. but not too sure about that.
Your processor fan might of died.. which most MOBO's these days wont boot w/o the fan running.
I suggest opening your PC.. cleaning it out with some compressed air.. and trying to boot it with the case open. Make sure all fans etc are running, etc.

[Dax_Brandy]

could be a failing PSU. you know when electrical components are already dying, there response time decreases or deteriorate.

[andreh]

Thanks to all of you who have replied so far.
I don't think it is the switch. I know it is not very healthy, but I shortened the power pins on the MOBO and it was just the same.

I opened the case and every fan spins. Another thing to mentioned is, that I can boot up fine when the machine hasen't cooled down completely - meaning aprox. 10min after shutdown. After that I have to use the sequence of pressing the power button again.