I have a Samsung PATA HDD (80gb) and a Seagate SATA (750gb) with Windows 7 ultimate loaded on both. When PATA is disconnected and I try to boot from the SATA HDD; it shows disk boot failure. I checked SATA HDD for bad sectors and with Ubuntu SMART scan. No problems with the disc. SATA is also detected in bios and boot screen. If I reconnect PATA; any of the two OS could be accessed. Why PATA is used as a initiator for booting?
My MB is Gigabyte MA78GPM-DS2H. Processor AMD PhenomII X4 955, RAM 4gb.