This is not going well. Everything's in and looking spangly but it goes into a boot loop when powered up. It switches on for about 4-5 seconds then shuts off and powers on again ad infinitum.
So far I've tried unplugging GPU, isolating other peripherals, fans, drives, USB cables etc.
Any suggestions before I'm forced to rip the CPU heatsink out?
ETA: Don't mind me... I'd forgotten to stick one of the power cables into the mobo!