Windows 2000 Server Start Button Sticks

I have two different servers (different locations) that are domain controllers on a simple 1-server network. Both have Windows 2000 Server as their operating system. I am having a problem with the start button sticking in and not doing anything.
This is occurring ramdomly. When this happens, I can only fix it by restarting the server, then it may stay working for 4,5,6,10 days before it happens again. I have reviewed article Q262076 and have not had this fix the problem. I also have thelatest Microsoft service packs and security fixes applied.

Any suggestions?