HKEY_LOCAL_MACHINESystemCurrentControlSetServicesMsahci
is set to 0. Changed IDE to AHCI mode in the BIOS. Windows starts but it's stuck at 'Starting Windows' for over an hour before I switched off the machine. I booted from the Windows DVD to get into Startup Repair option but it's also stuck in 'Starting Windows' screen! I did another try to do the same but without the DVD using F8 to get the boot menu. Same result. So 3 different ways are giving a stuck 'Starting Windows'. I don't know why AHCI mode is causing Windows not to boot properly.