So I recently got a new HDD. Put it in and started reinstalling windows onto it. I'd got my external drive plugged in at the same time. Install seemed to go fine, no problems, everything seemed alright. Today, plugged the power in, turned off the external HDD as it was making a noise. Turned the PC on, went past POST, got to the little white flashing cursor thingy, and stuck. Restarted, same thing. Turned on the external drive. Boots up fine. In the Storage Management thing, the external drive is apparently : System, Active, Primary Partition If I try the repair function after booting from the windows disk, without the external HDD on, the box where it asks you to pick the OS to repair, there isn't an OS listed. So, it seems as though the install details etc went onto the external drive, or the MBR or something. Is it possible to get it booting properly from the correct HDD without reinstalling windows again. I'm not overly bothered if I have to reinstall, its just easier if I don't have to. Cheers.