Windows 8 Stop Automatic Repair on boot

I tripple boot my computer Windows 8/Linux/OSx with the default load as Windows. Every once in a while, I will start my computer, walk away, and then realize I wanted a different os than Windows, so I'll hold down the power key and shut down the computer (Windows 8 takes eons to load, and then you have to log-in to shutdown the computer, which takes even longer, 2-3 minutes on my desktop).

Windows, of course, thinks that it failed to start up. In previous version of Windows, this was no problem. I would just cancel out of boot repair/disk check, and it would start up fine since there was really no boot problem.

In Windows 8, however, there is no way to cancel, so it attempts boot repair, but fails, either a) because there is nothing to repair, or b) because I have no admin account on the machine.

Which leads me to the next problem. I can't access anything in the trouble-shooting, like command-prompt or the boot repair menu because it says "there aren't any administrator accounts on this PC," even though my user account has admin rights over the machine (though, I don't think the Windows "admin" account is enabled for security reasons).

Anyway, I can't enable the admin account because I can't get to command prompt. I can't get to command prompt because I can't enable the admin account. I can't stop startup repair because I can't get to command prompt. I can't boot the computer without disabling startup repair.

I upgraded downgraded Windows 8 overtop of Windows 7 so I have no install disk to use.

Any suggestions? (other than deleting that partition and just booting up into Linux and OSX from now on?)

Here's the error message I'm getting:

You need to sign in as an administrator to continue, but there arent
any administrator accounts on this PC

Answer

Fixed it. I opened up my computer, unplugged the other hard drives, and boom, it worked. Startup repair worked.

It did this to me on install. Why does Windows 8 assume it's a) the only drive on the computer? and b) that it is the boot drive??? Windows 7 never did this.