If it can't find the master boot record then it will say missing operating system, or invalid boot disk, inser proper media etc. This should happen with no ide hard drives connected (or one without an operating system on it). Boot issues could be a number of things, simple process of eliniation to start, change ide channels, try 1 device at a time, swap the ide cable, change power connectors over, reset the bios to system defaults (then change accordingly)