My PC froze while trying to install iTunes after one of the files became corrupted; it shut down, restarted itself and came up the BOOTMGR error.

I'll try unplugging the non-OS drive in a bit, but I don'tthink it would have tried to boot from the wrong drive for no reason..




(Thinking about it, in the Windows installation repair thing, it was calling my Primary OS drive, previously C:, it was calling it .... which is a little confusing..)