Civ fails to launch, minimizes to taskbar

I've been playing Civ4 on Win 7 for years without a problem. In recent weeks the game fails to launch after the computer has entered sleep mode. The game will cycle through all the initial loads, but when the spinning wheel icon appears, it minimizes to the taskbar. Choosing "Launch Civ4" from the taskbar has the same result. My drivers are up to date and I am using the game from my HD, not Steam. Has anyone else faced this problem? Or better yet, found a solution?

I never use sleep mode. It is always better to reboot your computer at least once per day to clear out the 'junk' that builds up in memory.

I always do a full shutdown at the end of each day, and start fresh the next day - effectively rebooting once per day.