Ok:

Install BG2. Start BG2-Config.exe once. Save config.

Disable Windows' UAC (run msconfig.exe, tools, UAC start)

Execute BG2Fixpack.exe and point it to where you installed BG2. Fixpack is extracted and should start setup-bg2fixpack.exe in a DOS-command windows. If not execute manually. type in the options when asked.

Same for widescreen mod. Widescreen mod asks you for screen resolution.

Do not install english fixpack if you install bg2 fixpack.

Do not run config again. if you have to config again, modify your baldur.ini manually via a texteditor.

I wish I even got that far, I can't seem to open any of the three downloads it gives you once you purchase the game. Can't seem to find a fix for it either. Haven't had this issue with any of the other games on gog.

What 3 are you refering to,
setup_baldurs_gate2_2.0.0.12.exe & the 2 setup.bin files?

Did you right click on the .exe & try run as administrator?