Computer keeps turning on and off

[TKAGriever]

The problem I am having is with a new rig I was putting together. When I start the computer it keeps on going on and off without even actually starting. The fans startup and shutdown but I can't even get to bios. Its as if the computer gets just enough power to initialize the hardware and then it runs out. At some times it manages to bootup but after a while it freezes and there appears red and green dots/lines all over the screen in varying numbers every time.

Of the new rig the mobo (asrock z77 pro), the cpu (intel i5 2500k) and memory (kingston 2x4gb) are new and the rest come from my old comp.

Now my asumption is that something is overheating but as I have no external way to monitor the comp temps I don't know which one. One possibility I am leaning on is the power supply failure. Unfortunately I have no spare parts which so swap around to test this theory. I need someone with larger experience than my own to either confirm my theories or give me their own. I know it is difficult to judge without seeing the thing in action for ones own eyes but any help is appreciated.

[CimmerianX]

What I would do:
1 - remove all non essential devices. Pull all addon cards, cdrom, anything that draws power.
2 - check to make sure all fans are turning
3 - Did you use heatsink compound when installing the heat sink/fan on the processor? You should
4 - Check the mobo and proc specs, make sure your Power supply is large enough to support the power requirements. I would assume yes unless you have a really tiny PS.
5 - Testing with another power supply would be best.

[Trecker]

One may not so much toucht problem is a sticking power switch. Similar to that is if there is a short like some wire has lost insulation and touching ground (case). And finally one more, your cmos is set to clear. Of cause you can have a component problem, but to check these out before might be helpfull.