Try this:
Go to "My Computer" then find the CD, i.e. "Sim City 4 (E:)" or whatever, open it and then find the file that automatically runs the game it might be called like "SETUP" or something like that, right click on it then go to properties then click the compatibility tab, then check the "Run in compatibility mode for:" and choose a mode i.e. "Windows 98" etc
This worked for some older games when I got my new comp
Although if Sim City 4 is a new game and says it runs with XP then its prob ur drivers etc