Sorry if this has been asked before but I have searched but can't find the answer. I have an amd phenom II x2 560 and with win xp pro 32bit I can change to hybrid and unlock all cores and it tests out ok with prime95, it will even run stable overclocked to 4000ghz on 4 cores. When I try other hdd with win 7 pro 64bit as soon as change to hybrid it will not boot even with cores 2 + 3 disabled. I have tried slower clock speed, different voltages, different cores enabled but in hybrid no boot. Hope you can help.
mobo - gigabyte ma78lmt-us2h (xilence nb cooler + fan)
psu - 750w
cpu - phenom II x2 560 black (arctic freezer 7 pro rev 2)
mem - 2 x 4gb corsair ddr3 1600mhz
hdd - 1tb samsung (win 7 pro)
hdd - 160gb samsung (win xp pro)
graphics - radeon hd670
did you install the OS with the same MoBo? If not, it wont recognize the OS. Sorry if this seems like a very simple fix, but its the first thing i would want to check. OS's attach themselves to the HDD & the MoBo.