A few days ago GOG galaxy was not wanting to load my games and it kept saying unable to load game data, I tried to delete then reinstall GOG galaxy but it said that there was another instance open and I could not download it. I would appreciate some tips.

same here. can't open it at all. its been "opening" for last 2 hours and nothing. Reinstalling doesn't help

1. Make sure GOG Galaxy isn't running. Check the tray area of the taskbar, as well as Task Manager.
2. Uninstall GOG Galaxy from Control Panel.
3. In the File Explorer address bar, paste C:\ProgramData\GOG.com\Galaxy -- move this folder elsewhere for safekeeping, like the desktop.
4. Get the latest version and install it.
5. Hopefully now GOG Galaxy starts up and begins to import your game data from your account. Once this is done, you can click the cogwheel in the top left, then choose Add games & friends, then Scan folders for GOG Games to add games that you already have installed.