Ah, i figured it out, i have to change it before you load up the game fully..
quote:
Originally posted by http://www.gtaforums.com/index.php?showtopic=188753&st=0
Problem #16
There are problems changing the resolution of Vice City; and/or the game crashes upon 'ALT+TAB'ing out back to the desktop.
Solution: It should be noted that the resolution can only be changed upon initially running the game (i.e. not after a gameplay has begun). Therefore, quit Vice City. Load it up again, and before anything else is done, simply head to display options and change the resolution. You must select the desired resolution with the directional keys and hit Enter to confirm.