My computer has two drives, both 1 TB.

One has Win7 already, and was listed by the Win7 disk as primary.

The other drive, which has an older Win on it, I wanted to be wiped. It was listed by the win7 disk as system.

Because I could find no other convenient alternative to formatting (using disk manager didnt work, i would get an error JUST saying it could not be done), I booted off a usb drive containing win7 iso. From using the win7 setup, I selected the hard drive that I wanted to format, and went advanced driver options and selected format.

Afterwards, the hard drive that I wanted clean was listed as having full spaces available, while my main drive was unchanged in spaces available.

I quit out of win7 setup, and restarted, but the system would not boot from my main drive. Even removing my supposed wiped drive would not allow me to boot from my main drive. It was not a boot priority issue, it simply would not boot.

What happened, and what can I do

Because I cannot find the edit button, here is a double post. Sorry in advance.

EDIT: To check the status of my main drive, I installed win7 onto the new drive which I formatted.

Booting up, I can see that my main drive that is unbootable still retains ALL of its files functional. However, it just cannot boot from it.

This sounds more like a Windows 7 support question, than a disk problem, based on your list of the events and lack of errors.

I suspect that Windows might have removed the "active" flag from the previously bootable main Windows 7 partition, when you booted from the Windows setup ISO image - if true, this would account for the symptoms which you describe. That hypothesis is easy to check in Linux/Unix, but I have no idea how you would confirm it using the utilities available in Windows 7, since I don't use that...

a) What is the exact message when you try to boot from your "main" Windows 7 disk?

b) Have you already checked that the partition which you want to boot from, is in fact marked as bootable in the partition table on that disk?