Boot windows 7 with no partition marked as Active?

I have windows 7 installed on my primary drive, but my laptop doesn't think there is an OS installed.
I don't know how, but I wonder if its been deactivated..

I was having trouble making a system image backup because windows thought there were system files on my D: drive which is just Steam and about 20 games, as well as my C:Windows. So my backup was about 600gb. I went into Disk Management and wanted to disable my D: somehow to make the backup. I right-clicked the Steam D: and marked as active and I didn't get the usual warning that this should have an OS installed if you mark as active. I deactivated it through command prompt and restarted the laptop. I never touched the C: in Disk Management but now my laptop doesn't think there is an OS installed..

Is there a way I can make the proper partition active or boot windows from a disk without reinstalling?
My Steam D: is made up of 2 harddrives in raid0 with 600gb of games on it and I'm really hoping I don't have to re-install windows.

No It won't boot, It says no operating system found. Try disconnecting any drives that don't contain an operating system.

I actually do have a Win 7 cd, and I tried startup repair a couple times but nothing changed.

Could I Mark partition as active through command prompt?

Everything that can be done is here for Troubleshooting Windows 7 Failure to Start.

If you don't Mark 100mb System Reserved (preferred if you have it) or C Partition Active
before attempting repairs then it will NOT repair. You also may need to run Startup Repair - Run up to 3 Separate Times.

If this fails then start at the top of the steps because it may also not repair until disinfected.

Thanks, I set the system reserved partition as active and ran repair, and it booted right up. Now I just need to figure out why windows thinks there are system files on my Steam Harddrive so i can make a system image of just the C:

Here it is now