I would like to know more about the problem you are having so we can get it fixed. Change the resolution one more time and let the problem occur again. Close the game then go to "\My Documents\My Games\PolMachine2008\Debug.err". You can open the file with notepad. Please post the contents of that file here so we can try to figure out what is happening, and also get some stats about your computer.
Assuming you've already done the above, I'll now answer your question...
The options screen writes your preferences for the game to a file located at "My Documents\My Games\PolMachine2008\prefs.ini". It's just a text file, and can be opened with notepad. You can edit the file to change your resolution.