I downloaded and played a game on another computer but now I have a new laptop that I'm trying to download the game on so I can play. When it finishes the download it says "Error 2" and allows me to retry but it keeps giving me the error and the option to retry over and over. How can I get the game to download so I can play it?

Have you cleared your browser's cookies / cache for GOG and then attempted to re-download the game as a GOG Offline Installer? This tactic often fixes unusual download problems like the one you described.

Alternatively, have you tried using a download manager, such as https://jdownloader.org/download/index to try downloading the game itself?

'failed to finalize'. Hmmm...

I suspect it isn't getting around to installing dependencies (or registry access it thinks it needs) as that's usually the last 7% of the install. It's entirely possible you could find your installed game and just be able to run it

So to try: Close Galaxy, Reopen but with right-click and 'run as admin'.
Then try installing again.
When done installing close galaxy and open normally to close out of admin state.