It sounds like you installed 7 on the SSD while the old drive was still plugget into the machine. Can you confirm this? If so, Windows, upon install, may have assumed the BCDStore to be used is still the one on the old drive. So, that is still a system drive, and actually the one being used to boot.

To test that, try to boot after disconnecting the old drive.

If the system won't boot, you'll have to move the BCDStore from the old drive to the SSD by using BCDEDit.

If you think this may be the case, let me know if I can help more.