Hello, after downloading parts 1 and 2 of BG2:EE (without gog galaxy) I launch the .exe installer but it asks for disk 1.
How can I install it???

What are the exact names of the files you have, and are they both in the same folder with administrative permissions?

Where did you install it? Did you install the patches as well (not sure if the .exe is updated to the latest or not)?

It is not installed yet, the problem occurs when I want to install it. the files are "setup_baldurs_gate_ii_-_enhanced_edition_2.3.67.3_(hotfix)_(10672)-1.bin" and "setup_baldurs_gate_ii_-_enhanced_edition_2.3.67.3_(hotfix)_(10672).exe And yes, they are in the same folder and with administrative permissions

Those are very long file names. That means if you also have them stored in long nested folders, or are trying to install them into long nested folders, the operating system may have trouble. For troubleshooting, create a new folder on your C: drive and call it simply 'Downloads'. Copy/paste both files to there and then rename them to:
setup_bg_ii_enhanced.exe
setup_bg_ii_enhanced-1.bin

Now try to install, but do a custom installation and install to C:\Games\

That will eliminate if there is a name length problem.

I may be saying something stupid here, but aren't you supposed to mount/burn to iso a .bin file? I remember when I downloaded games and they had bin and cue files that's what I did to install them. I just did a google search and it says when there is a .bin file but not a .cue file try this

http://www.wikihow.com/Open-BIN-Files

And OP said it asks for Disc 1 so doesn't this mean you have to mount something and then point the installer to that drive that has the contents of disc 1?

I think that is only true for cracked games downloaded from illegal sources. For GOG you must not do that. ".bin" is just the names of the extra installer files. GOG usually divides installers into multiple files to make it easier to download if the files are too big. So you will have like...

Amazinggame.exe
amazinggame1.bin
amazinggame2.bin
...

They all need to be in the same folder and must be run with admin privileges. Hickory gave the most possible solution to the situation. And the only reason I know for such case.

A .bin file is just a file extension that stands for 'binary'. In other words it's a binary data file that (in this instance) the installer recognises as the data to process. It is not restricted to any program or application. The .bin and .cue files you talk about were two different files needed for burning (.cue is a text file laying out disk format, and .bin is the actual binary data needed to be burned to the disk). While many illegal copies use/d that format it was not developed for that purpose. It is simply a format, much like .zip, .exe etc. that is used by various burning software.

Bloody hell, Hickory was right, it was the name which was to looooong. (it was already in the C:/download file) just the freaking name...

at least, now people know.

Thanks for the feedback.

True. But I wasn't trying to explain the general use of the bin files. My reply was referring to burning/mounting which you shouldn't do for GOG files. I don't know any digital store that sells you a program/game and then asks you to mount/burn it.

Of course like you said, You may own a disk version of the game and then make extra copies for safe keeping by making .bin or iso files of the disk. Which I believe is still illegal but in the grey zone.

Great job solving an other case Hickory ;)