it is a few years since my last install, i remember there used to be a way in which i could install BG1 classic+addon and bg2+addon by copying and pasting certain files and then resulting in a continuous game.

does anyone know what i am talking about? i did not find anything by searching for keywords realting to this topic either in this forum or via google

thanks beforehand

I know there is an EET trilogy mod that merges BG1 + SoD + BG2/ToB altogether for one seamless playthrough, but unfortunately I do not know if it would work with the classic non-EE versions of the game. (My guess is No, unless the mod maker made a version that I haven't heard about.)

It is definetly a bit more involved than just copying a few files.
Back in the day there were two different projects.

Baldur's Gate Trilogy - fused both games and their addons into one continuous adventure:
http://www.shsforums.net/files/file/54-baldurs-gate-trilogy-weidu/

Tutu - moved BG1 into the BG2 engine:
https://www.pocketplane.net/bg1tutu/

I guess what you want is Baldur's Gate Trilogy.

thanks for your help! i will try that

the difference is what engine is used and there for what mods can work with it

Trilogy keeps the Bg1 engine and is what you want for really old mods but the down side is spells changed between Bg1 & Bg2

TuTu [or easyTutTu] converts the Bg1 part of the game to use the Bg2 engine so mods \ spells etc act in the same way through-out your travels... if you want to play with mods then TUTU is what i recommend because most of the newer ones assume it

those are for the old engines... current mods are made for the EE builds so it matters which build you actually want to play