Systen Can't find Operating System Unless I disconnect my

I have a new internal HDD. When I first put Windows 8 OS on it I needed to disconnect my External HDD because I was getting the error (don't quote this):
"Can't find operating system. Disconnect any drive that doesn't not have an operating system."
It booted fine when I disconnect the External HDD.
It stopped doing this until today. I need to disconnect it when IU reboot.
I believe I ejected the External by mistake and tha6t5 screwed everything up again.
I entered the BIOS and I don't see the External HDD there. Only my internal and my cd/dvd drive.
It currently looks for an OSA on the cd/dvd first.

Any ideas how to fix this??

James

Fixed now.
The Internal and External HDDs weren't listed separately in the BIOS "Boot" section. They were listed as HDD group.
I to enter that and disable the External HDD in the boot sequence.
And now all is well.

James