Have you tried to set the compatibility mode for the game? I'm using XP and set the compatibility to windows 98 before I started the game. The one time I had trouble like what you describe, I exited the game with "control, alt, delete" and restarted it. Had no trouble after that.
To set the compatibility mode, right click on the game icon, click on properties, then click the compatibility tab. You can set it from there.
Let me know if that helps...and good luck!
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