I don't think OOTP4 works in 800x600 mode (game requirements say 1024x768 minimum screen resolution ), so if that is the case I doubt v5 will work in that resolution either
. Is this an older monitor or very old video card? If I were you I would scour the net for a monitor driver update and a video card driver update, and update your machine with them. Unless the card or monitor are from pre 1996 or so you should be able to get it to work in higher resolution. Good luck!