Heres a strange problem for you.
AMD x555 Black edition
Kingston 2GB DDR3 1600MHz HyperX Memory 1.65V Non-ECC CL9 KHX1600C9AD3/2G
Nvidea 6600GT (upgrading soon)
Built system instaled Vista Ultimate worked fine (apart from Code 10 error on my USB mouse) turned memory upto 1600 unlocked all 4 cores and had running at 3.3 all running fine. ran a few stress tests and no problems at all.
Upgraded to windows 7 instaled in the end (had the problem of instal not getting 62% then stopping).
But it refused to boot got to just where the 4 colour dots that turn into the flag appear the nothing.
So i reset bios back to default and hey presto it booted.
Then did a clean instal win 7 went in fine booted ok.
Unlocked cores again and it refused to boot.
Formated and reinstaled Vista boots ok when unlocked
Tried windows 7 again wont boot when unlocked
This is driving me mad anyone have any ideas ?