How long has it been since the game last worked? And can you remember the changes that you might have made to your system since the last time it worked?
Which OS are you on? If it's Vista/Win 7, then try disabling UAC from Control Panel. Also, check your firewall settings to make sure it's not blocking the game. Same with your anti-virus.
If you have Win 7, then you can also try running the game in Win XP SP3 or Vista SP1/SP2 compatibility modes.
Additionally, try deleting all files from the Settings folder. Read this
to locate your Settings folder.