Made 2nd hard drive inactive through windows CMD. Computer won't boot from primary HDD

[Aratnacla_N]

Hi,
I made my secondary 1tb hard drive inactive through the above process. I was told to restart my computer so that I could reformat it. I had to do this because my 1tb hard drive was set up for windows 7, and I was on windows 8. However, now my computer says
An operating system wasn't found. Try disconnecting any drives that don't contain an operating system.
However, I have windows 8.1 installed on my C: drive that is still active. I have gone through BIOS to ensure that my C: drive is the selected first boot option, but I'm getting this error. I have also disconnected my supposedly "inactive" 1tb secondary hard drive. How can I fix this?

Here was the guide that I was following (method 2):

http://answers.microsoft.com/en-us/windows/forum/windows_7-system/how-to-format-a-system-partition-created-by/27fae440-2c27-4285-8703-7f66ee128030

 

[popatim]

Apparently you installed win8 to the active harddrive while the inactive one was still plugged in so winowds wrote boot files to it.
withthe inactive drive data cable disconnected - Use your install disk to run startup repair, you may need to run it a few times, and it will eventually figure out whats wrong and write the boot files onto the correct disk.

or you can use diskpart to activate the old drisk, boot up, and use easybcd to move the hidden system boot partition over.