On a system where the CPU and motherboard had to be changed, the Windows 7 installation doesn't boot up. We have tried changing AHCI to IDE and vice versa, but to no avail. When I Disable Automatic Restart on System Failure, it's a 0x7b error.
I have tried Microsoft's fix of disabling the Msahci service, but that didn't work. I also tried going a step further and disabling all the IDE drivers in the registry (setting START=0) and enabling all AHCI drivers (START=3), and ensuring the BIOS is set to AHCI storage. Any other ideas?