[SOLVED] BOOTMGR is Missing Windows 7 / 2 drives

Hi,

I've just bought a second hand PC with 2 SATA hard drives, one of which has Windows 7 installed.

I'd like to remove the drive that doesn't have Windows 7 installed, but when I do and reboot, I get the BOOTMGR is Missing error message.

I've tried running startup recovery, but it fails, saying the issue can't be resolved automatically.

Can anyone suggest how I can resolve this issue?

Thanks in advance.