New hardware - Can't boot!

I got a new Motherboard and CPU yesterday.
After finally getting everything together I tried booting my system.

Then something very strange happens I haven't experienced before.

When I press the power button my computer starts to boot, but switches off again after half a second.
Then it waits for two seconds and starts up again by it's self.
Everything starts up as normal (HD's, CS-Rom's, Fans) but my computer screen remains black (sleep mode).

I've tried to reset CMOS/BIOS, pulled out two of my RAM chips, then later changed to slots my two remaining RAM chips where in.
I've also tried booting without HD's (thinking I maby had a weak powersupply). Still only a black screen.

Anyone know what might be wrong?


Current Hardware:
Core 2 Duo - E6850
Asus - P5B Motherboard
4x - Corsair 512MB RAM (533 MHz )
NorthQ Powersupply (400W)
GeForce 7800 GTXNew hardware - Can't boot!
i'd say your new mobo or cpu is bad. power supply is also a possibility.New hardware - Can't boot!
A colleague of mine thinks it might be my Motherboard.

As it is now my MB doesn't support my CPU.
I have to upgrade my BIOS for it to support a 1333MHZ bus CPU.

I thought it would still be able to boot so that I could update by BIOS with a boot disk.
Could this be the case?
I just ordered the same MB and CPU. I would really like to know the answer to your problem. Anyone?
i think you may have incompatible ram or you need the bios updated with a different proc
Happy, Happy!! Joy, Joy!!

I fixed the problem!
I needed to instal my old CPU, then update the BIOS to support 1333 CPUs.After that it worked like a charm!

sound like mob or underpowered p/s
[QUOTE=''therog2'']

Then something very strange happens I haven't experienced before.

When I press the power button my computer starts to boot, but switches off again after half a second.
Then it waits for two seconds and starts up again by it's self.
Everything starts up as normal (HD's, CS-Rom's, Fans) but my computer screen remains black (sleep mode).[/QUOTE]I also experience the same problem with my new one - but it ain't broken - it does that power on then turn off for 3 secs then it auto powers back on again, but from there it's all fine - wierd. It's started occuring after I pushed my FSB pass the 260mhz mark...