Strange powering on problem, help needed plz.

[BigJim(UK)]

Hey there, I have a strange problem, when powering on my pc, i press the button, the pc starts to power up, then it turns off, then it automatically tries again, sometimes it will then turn on fully, and the cpu coolers starts spinning and everything is fine and stable, but sometimes it does this switching on and off about three to four times before it finally runs.
Any thoughts on what could be causing this?

Thanks.

 

[BigJim(UK)]

It stays, i have lowered to 450 x 7 and it went on first time, once its on its great, just seems to take a couple of goes before it starts fully!

 

[BigJim(UK)]

I have noticed that while running 2 x copies of orthos and TAT, my CPU frequency changes by 1mhz up and down, and cpu-z is reporting my voltage as 1.392, but i have it set to 1.45. Is this likely to be causing problems?
Speedfan reports my +12v as 4.16, could this be a glitch as im sure if it was this i wouldnt be able to run games etc stable.

Edit: This is starting to bother me now, Everest says my +12v is 4.16
And Cpu-z says my vcore is now at 1.219. Im a bit worried!