I have a brand new system that just wont stay on, it comes on for 1 second and then turns off. tested system with multiple Ram types and multiple PSU's, also had 2 cpu's.

Tested using only mobo, cpu, ram and psu but it gets up to number 19 in checks before switching off.

Have a new one ordered through amazon but I want to check if anyone knows what might cause it.

One thought I have had is that i am using i7 3820 apparently there is a bios issue which requires an update, some people say it is required some say its just to optimise but as I cant get into the bios screen not sure how to do this.

Mobo has instant flash bios if i have that right then i have got the file on a fat32 flashpen and plugged it into the pc but it still makes no change, wonder if im doing this wrong, or if anyone knows what else might be causing it

thank you all