Thank you. I'm not sure if that is the installer that I used. It certainly looks familiar but I had been previously trying to do the BGT, which I believe uses that. I'll look into it and everything else that has been so kindly recommended. Time to start from scratch again.
EDIT: Just thought of this and don't know if it has any bearing. I'm using BG from the Dungeons & Dragons Anthology Master Collection. I do not have the Extended Edition.