The computer WAS working when I first built it, it switched on and booted into the OS, however it required a re-install as I expected since the Hard Drive was from my old system. I switched the PC off and removed the hard drive from the back of the chassis and plugged it into my old PC to transfer the data off, after this had completed, I put the HDD back into the new system and plugged and powered on, however the computer turned on for a split second then switched off in an indefinite loop. I have tried the following:
Tested a different PSU
Removed all cards from motherboard
Turned it on with a screwdriver on the power pins on the mobo.
made sure none of the power cables were making contact with the case
Unplugging and replugging the kettle lead
Resetting the BIOS, waiting 2 mins with the BIOS battery out of the motherboard and leaving the kettle lead out of the PSU
None of the above worked, I'm stuck for any more ideas, suggestions are very much appreciated.