Windows 8 install error, stuck in a loop

Hello, I had windows 7 dual booted on my macbook pro, tried to then upgrade to windows 8, anyway after installing windows 8 I get to a screen where I can either tell it to proceed with loading windows 8 or the second option is I click a button and it rolls back to windows 7. I was getting an error like "windows restarted unexpectedly" after seeing the blue windows 8 logo, so my comp restarts. The windows 7 rollback worked the first time. Then I tried using the same disc to upgrade to windows 8 again.

Got the same error, except this time the rollback function doesnt work. My computer just restarts. So does anyone know how I can get the rollback function to work again? I want to avoid having to redo my windows partition. Thanks!

Since Windows 8 is not officially supported by Apple (Boot Camp Assistant) you're on your own with this one. You likely overwrote the Windows 7 MBR with the two attempts to install Windows 8.

Upgrading Windows 7 to Windows 8 is supported on a PC that's running Windows 7, but you're running it on a Mac which uses EFI not a BIOS. So there's no way to tell if the MBR is good or not, but I suspect you overwrote it and will likely have to reinstall.