Windows 7: Windows 7 8 dual boot problem

Hi,my problem is that i have 2 hdd's one has windows 7 in it the other windows 8,well i didn't like windows 8 so i wanted to take one of the hdd and use it as external,but if i take the windows 8 hdd off it says that i can't boot up anymore cause the windows 8 hdd is missing(It was giving me an option if i wanted to boot 7 or 8 before)what do i do to take off the windows 8 hdd and still be able to boot into windows 7?Thank you

Startup Repair

Unplug the HDD with Windows 8 on in it and follows the directions in this tutorial. Note: You may have to run startup repair up to 3 times. Once the disk with Windows 7 boots on its own, then you can plug the drive with Windows 8 back in and reformat it if you wish.

Startup Repair
Note: You may need to do startup repair 3 to 4 times.
Startup Repair - Run 3 Separate Times

You must Partition - Mark as Active the Windows 7 partition or it's 100mb System Reserved partition (preferred if you have it) Active first before running Startup Repair - Run 3 Separate Times or it will NOT work to write the System Boot files. Unplug all other HD's first.

If you have any further problems plug back in the Win8 HD to make a screenshot of your maximized Disk Mgmt drive map using the Snipping Tool in Start Menu, attach using paper clip in Reply Box.