Windows 7 unaccsessable - Windows 8

I installed Windows 8 on a separate hard drive from my windows 7 installation so that i could revert back if needed. however when i boot to my windows 7 hard drive a windows developer preview boot selection screen comes up and has windows dev preview and a windows 7 option. If i click on windows 7 the screen goes to black and then the boot fails and the computer restarts.

Your Boot Configuration Data has probably been changed by your Windows 8 installation. You should have disconnected the Windows 7 drive before installing Windows 8. If you had made backup of your Windows 7 system partition before the Windows 8 installation, and have a program to recover this backup (such as Acronis True Image Home), you can install that program on your Windows 8 system and then restore the Windows 7 system to the drive on which it was before the Windows 8 installation. After that, you will need to enter the BIOS make sure that your computer boots from the Windows 7 drive. If not, you will have to edit the BCD or disconnect the Windows 8 drive and repair or reinstall Windows 7 on the original drive.