It wont start anymore. I installed it and it was working fine at first, I installed a few games and it was good.
Then I closed it and it won't open. An error message comes up saying "Essential components needed to start GOG Galaxy are missing. Please reinstall the application." I uninstall then reinstall and the same message comes up. I've tried this several times. I've also redownloaded the installer and tried again but it still has the same error. What do I do?

Try searching in Galaxy beta official thread.

here

gog galaxy essential components needed to start gog galaxy are missing.

i need help i have tried to uninstall the app but when i go to change or iuninstall apps i cant find it

i also have tried to uninstall galaxy client by typing "sc delete galaxyclientservice" and nothing seems to work help lease

Try downloading the newest installer and installing it directly in the same place it is installed now.