MSVCr71.dll keeps getting deleted
I installed Civ4 with no problems. Ran it and it works fine.
Then next day I try and it complains I need to reinstall because msvcr71.dll is missing. I uninstall, reinstall and everything works fine.
Then the next day, it complains that I need to reinstall because msvcr71.dll is missing...
Between these events, the machine is up and running but nothing (other than folding) is actively happening.
I don't really want to keep uninstalling and reinstalling. So what is going on, and how can I permanently fix it!.