So I just built this computer and I had originally installed 3 Hard drives, 2 SATAs and 1 IDE. I took the Sata out and the IDE out. Now when I reboot my computer it says that Disk Boot failure insert system disk and press Enter. I know I installed the OS on the main HDD that is still in the computer. And Bios detects it. Under Standard CMOS features it says: IDE Channel 4 Master [Samsung HD103SJ] (samsung hdd) IDE Channel 5 Master [ASUS DRW-24B1ST] (my dvd drive) 0-3 Master & Slave are None I have First Boot Device Set to Hard Disk, Second: CDRom, Third: Floppy Also under Hard Disk Boot Priority: 1. Ch4 M: Samsung HD103SJ 2. Bootable Add-in cards. Windows was working perfectly and everything was good till I took the hard drives out this morning.