it depends on what options are available in the screen rez selection menu either in game or on the games config menu on the installer or in the main install folder...
some older games only run at 4/3 or 5/4 res such as 1024/768 or 1280/1024
games like need for speed most wanted for instance later got patched to run on 16/9 monitors but that was a community patch not all older games got them.
most games from the 2003 onwards to 2007 supported up to 1680/1050 then after that most new games supported 1920/1080-1200. pre 2003 your likely to be stuck at 1280/1024 max. unless like i say the game got an updated rez patch...
some games like f.e.a.r just left it up to the gfx card and would run any available rez but if you went over the standard for the day 1280/1024 you would see a message saying the game was not optomized to play at this rez and may cause issues. it rarley did as f.e.a.r was well written (well after 7 patches
).