Ok, I've more or less narroved it down to the motherboard (MSI K8T Neo-FIS2R). 90% of the time I can't get paSt the (according to diagnostic lights) early chipset initialisation. But if it does get past that the screen and everything will come on, like now (this is my computer, first post was made on dads). So I'm beginning to wonder what I can do about it? In any case I'll check the GPU temp now.