Just installed BG2 SoA on my PC (Vista) and the game crashes when I equip any of the characters with a great sword, it also crashes when trying to view certain items description.
1. Did you install to the "programs folder"? Move (un/re-install) it to C:\\games or some such. 2. Is it the GoG (already patched) or a Disc set... needs a patch? 3. Sounds like there are files missing, did you do an compleat install or some kind of space saver... If a disc then try cleaning it. 4. What mods? I could keep going but hopfuly you can get it going by now.
p.s. We have no idea what is on your computer... MORE INFO,
Just to clarify what USSNorway said, by default Vista will have SoA install to a C:\\Program Files (x86) folder. This won't work due to UAC (user access control) feature of Vista. Instead uninstall by going to Start > Control Panel > uninstall a program. Select Shadows of Amn.
Then on the re-install be sure to change the program path to like C:\\games\\black isle\\BG II SoA like USSNorway said. This could be your problem. Also if you have original discs you do need a patch. Be sure to get the right one, there's one for SoA only and another if your SoA has the Throne of Bhaal expansion.