GoG installer doesn't download my BG2 game even after it goes through the installer. Also why is the reguler download and installer in three parts?

The GoG installer doesn't download anything. You download the game and then install it. If double clicking on the exe file doesn't trigger the installation process, we need to know what happens instead. Do you get an error message?

Sounds like you are using the browser version, this game is huge and is divided into multiple parts and slower and more likely to encounter problems then using the GOG installer 3.0.52.0 version which has less problems and installs faster. After the game installs into your PC and merges, their is a small magnifying glass symbol to the right of the game which opens the file in your PC and click the installer then it will take care of the rest.

I get an error message telling me the file is corrupted when i try to install the game. what can i do?

Same problem as iamholmes. It tells me the exe file is corruoted and re-download. Done that three times. The other two call my VLC video player which reads them as UNDF (undefined) file types which cannot be processed