Fahim: Hi i have never played BG series so i bought the definitive dungeons and dragons set during the summer sale,
isn't it possible to play the vanilla game directly after the gog installation ?
Yes, you can play Vanilla BG1 without mods but I would recommend at least installing the BG fixpack (from Gibberlings3) as it removes some bugs that could otherwise crash the game (you can say 'no' to any 'optional but cool' options to keep it vanilla) - read the readme for details of what it does
Edit: Hmm, can't seem to find the BG1 fixpack to link to it - Gibberlings3 has the BG2 fixpack and the BG1 Tweakpack
Edit 2:
http://www.baldurdash.org/BG1/bg1fixes.html - this has a lot of individual fixes and the fixpack all-in-one