1. Do NOT swap boot drives. Ever. It is a very bad idea, can cause driver issues, bluescreens, file corruptions, all kinds of bad stuff.
2. Where did you get Windows 7 Starter? Was it preinstalled? There should be a certificate of authenticity on the computer that it came preinstalled with.The key on it has never been used, you can use that to activate. If you do not see a key anywhere, download and run this tool: https://go.microsoft.com/fwlink/?linkid=52012
Look at the key type. Is it 2 - OEM SLP? Then you're screwed. Wherever you got Windows 7 Starter from is not legit, and they have scammed you. If it's anything else, you can use a tool like NirSoft ProduKey to extract the product key. Then reinstall Windows (ask me for installation media) and try to reactivate. If you can't do it online automatically, use the phone system.