alright. i am now quad core. using a p5k-e mother board. asus 8600 gt 512 2 gig ram. super happy. im running two hard drives with ide and one dvd burner sata. i am using a topsilent 500 watt power surply.

PROBLEM! the problem is when i turn my pc on it stays on for 2 seconds and then turns off... any ideas? cheers!

Have you read any of the previous posts regarding non-booting newly built systems? If you had you would already know many of the "any ideas" about how to troubleshoot your system.
Ideas like: Did you benchtest the motherboard before you installed it in the case?
Have you disconnected all the drive data & power cables as well as removing all but 1 stick of ram and any other PCI cards etc to see if it will boot up or at least give you a POST beep?

Have you verified that all appropriate power connections were made including any extra 4 pin CPU connection and possibly a graphics card power connection?

Are you certain the CPU was correctly seated and appropriate thermal pad/compound used? Was the CPU fan correctly connected to the motherboard header?

Are the front panel wires correctly attached to the motherboard header?

Is the powersupply a quality unit up to the task? Does it have dual 12V rails and how much amperage rating on those rails?.

I'm sure if you do a little searching through the archives here you'll find other suggestions.

I used to have a signature but it disappeared and I just couldn't be bothered writing another so please feel free to ingore this.

Did you benchtest the motherboard before you installed it in the case?

thats the only thing i didnt do. my mate is going to bring his power supply around to see if that works.

ill post up how i go

Excellent post by Richard59. My bet is on a poor CPU/thermal compound/heatsink install. You must be VERY stingy with the thermal compound.