[Mobhack]

Which is telling you that you are trying to drive the screen at a resolution your graphics card will not support. 800x600 support, as I have stated in the above posts, is not something that can be relied on by modern drivers. Perhaps you have had a driver update put in by windows updates?.

Try another, larger windows 4:3 resolution should you want to continue with full-screen modes. Perhaps 1024x768 will work?.

The 2 games should behave exactly the same since the graphics engine is the same - so if there is a difference, then something in your set-up between the 2 installations is likely to be different. You will have to find out what that is, if any. (You may have used Windows compatibility mode on the one EXE but not the other?).

If the game runs fine in windowed mode at desktop resolution - fine, that is the supported mode. As we have said before, the windowed 256 colour full-screen mode is now an unsupported mode which is only there because it's inherited from legacy DOS and early Windows 98/XP and it cannot be guaranteed to work from Windows 7 onwards.