DFI Infinity 975x wont post/boot

This is my first forey into Intel for many years so please bear with me if my question/problem is a bit nooby.

I have:

DFI Infinity 975x
Conroe 6300 with Arctic Cooling Freezer Pro 7 HSF
HIS X1900XTX
2x1Gb GSkill PC6700 memory
20Gb PATA HDD
Samsung PATA DVD-ROM
Tagan 1100w PSU

Before first bootup, I cleared the CMOS and then booted, went into BIOS, set the date/time and loaded optimised defaults. I then rebooted (F10) and realised I hadn't connected the HDD power supply. So I shut down completely, connected the power connector and then powered up. This is where the "fun" started.

It wouldn't post. After much tinkering (clearing CMOS, removing CMOS battery, moving and removing components etc) I've found that after ANY power down, you have to wait at least five minutes before powering back up.

Has anyone else observed this behaviour? Any help/advice would be much appreciated.

btw, my max OC at the moment seems to be 2520Mhz with an FSB of 360. I'm hoping for more. Should I?

those chips seem to be doing upwards of 3.6-3.7 but I'm not sure about on the infinity board, with the 375-380 wall I've read about. in response to your question I had some issues with getting my board to boot, requiring me to hold the power button down 5 seconds, but the power button on the board booted immediatly. never had any cold boot issues though