Go inot the BIOS and check the boot sequence and make sure you HD with your OS is in there. I have 2 WD SATA raptors in a RAID 0 and when I installed a new storage HD, it changed the order and put my empty storage drive as my boot device (between the floppy and CD drive). I had to change it back before it would boot again. You HD might have just hosed too, the motherboard monitor thing might just be a coincendence.