Hey out there!

I've just set up my new computer and installed GoG, once i log in i can't see any of my games. When i connect my old computer back on and log in, i can see them

Any idea what i can do ?

Sorry if it seems obvious, but your post doesn't make it clear - have you actually gone to your library, or just looked at the list of currently-installed games?

Yeah i went to my library, but i've done some reading and discovered that GoG doesn't share the games like Steam does account wide

Are you saying that by clicking the Library button at the top of the screen, you get no games at all?

Yup, i used to play Witcher 3 on my old pc, but i can't see it in my library now when using my new computer

Are you logged in? GoG has also had a lot of bugs with the login in the past. Could also try to logout and back in. Because if you are logged into the same account (with games your account owns), you should see them on either computer, although you'd have to install them to play them on the new one,

Are you sure you're logged into Galaxy? Do you see it in your library on the website (not in Galaxy)?

I'm not sure what you mean by this, but I assure you I can go to any computer (even one that isn't mine) and access my GoG library from GoG dot com.

Obviously he is using the Galaxy client ("installed GoG"), so apparently he is having some issues with Galaxy on the other computer.

Oh okay. Sorry.

I guess that's a generic problem with us non-Galaxy using old beards, and new users. When some new guy writes "Help i can't download my game!". we automatically think they are trying to download the standalone offline installers with their favorite browser, when in fact they are trying to download and install the game through the Galaxy client.

What do you mean by sharing? There is no such thing as Family Sharing in Galaxy, but this is sharing between different accounts. When we are talking about one account there are no differences between Steam client and Galaxy as you should install every game you want to play on every computer you want to play on independently. There is however a UI difference: in Steam client you see on the left the whole list of games installed or not. In Galaxy you see on the left only installed games, you should go to the Library page to find the others. Hope this helps.

Gog shares the games the same way Steam does. So logging in on a different Computer using Galaxy will show you all the games you purchased in your Library and you'll be able to install them. Same goes for logging in on gog.com and accessing the Library there.
As in your next post your where specifically talking about Witcher 3 - did you directly purchase it on gog.com or somewhere else?