Mapped Drive paths

In My Microsoft Windows 2000 (I’ve used it for a week, is all)my mapped drives occasionally apply a red “X” which hangs up my computer in finding paths to everything else I am trying to launch. I can remove the red “X” by making it think I am usingthose drives, but this only fixes the symptom. These drives are something I access off and on all day, every day, so disconnecting them is not an option. Has anyone else run into this?