pc starts after 15-20 minutes of powering it to turn on

[KartikSharma]

Well When I press power on button of my pc, nothing happens(Absolutely Nothing).
I have to wait for like 10-15 minutes.
After it ,my pc turns on at any random press.

But when I shutdown my pc and turn it on like after 2-3 minutes, it turns on at once.

The problem comes when I have turned off my cpu for like 30-60 minutes.

It is as if, my pc needs to get hot before turning on. :lol

Specs:

Core 2 Quad 8300(No OverClocking)
iBall Sprinter 500W v2
4GB DDR2 800Mhz RAM
Sapphire HD 6870 (No overclocing)
and a 750 GB HD

I got my PSU like 3-4 months ago only. So i m quite sure that it may be fine.

After my pc is turned on , I can keep it on for hours drawing all power by playing Battlefield 3 etc on ultra.
Help Needed urgently.

[ApPy10]

Can you go into Bios settings and check hardware monitor to show anything that is either reading below 3.3v or something. If it is reading below than that then it is a power supply problem, if not then it could be either overheating problem or thermal paste wear off from the processor. You could even try to clean off the dust from the inside of the computer and see if that makes any difference.

[KartikSharma]

Can you go into Bios settings and check hardware monitor to show anything that is either reading below 3.3v or something. If it is reading below than that then it is a power supply problem, if not then it could be either overheating problem or thermal paste wear off from the processor. You could even try to clean off the dust from the inside of the computer and see if that makes any difference.

1. I dont have hardware monitor in my bios.
2. How can it be overheating problem if my computer runs fine for hours.
The problem arises only when I have to start it when it is cool.
3. I think processor if fine coz my pc wont get power for like 15-20 min.
Even the fans would not move.

[KartikSharma]

Can you go into Bios settings and check hardware monitor to show anything that is either reading below 3.3v or something. If it is reading below than that then it is a power supply problem, if not then it could be either overheating problem or thermal paste wear off from the processor. You could even try to clean off the dust from the inside of the computer and see if that makes any difference.

I installed Hardware Monitor and this is what I got.