It looks as if you've either formatted your C: partition (and erased Windows) or at best just deleted the Boot loader/MBR.
There is a guide here on how to repair it - you will need a Windows 7 repair disk at least.
If you have no luck, then you've probably deleted Windows. If you previously made an image, you may use that to restore. If not, Windows will need to be re-installed from your recovery partition or disks.