You shoudl have the email receipt with Product Key. Now you need to find or download again the installer for your licensed version.
You should burn the ISO to DVD or write to flash stick after download so you have it for reinstalls and repairs.
There was no reason to restore Vista. You can reinstall Upgrade to a formatted HD. The booted installer will see an OS and allow use of Upgrade Key, or use the workaround to install to blank HD: Clean Install with a Upgrade Windows 7 Version
As stated, best move is to save externally a Windows 7 backup image so you can reimage the HD in 15 minutes using DVD or Repair CD.