tuuubes May 6 @ 1:29am
Possible fix for "640x480 issue"
So I might have stumbled upon a fix for the issue where the game isn't working. I tried setting up administrator privileges, running in compatability mode and nothing would work until I tried this.

I had plugged my computer into my HDTV, but when I unplugged it, my computer still thought I was plugged into my TV. Thus, after trying everything, I went into the screen resolution setting. I saw that my computer was locked to 1280 x 720, and that it still displayed as being across "Multiple Monitors".

To fix it, I pressed F4 on my keyboard (controls the 2nd screen function on Windows 8) and switched it from "Duplicate Display" to "PC Screen only". I then went back to the screen resolution setting and changed my settings back to 1366 x 768, and magically GTAIII was working again.

Hope this is any sort of help for anyone having the same issues I was!