W2K Shutdown Problem

I recently began having a problem with W2k that I am not able to shutdown my PC using the Shutdown option in W2k O/S. During the past week that I noticed this I have installed Window Works and thought this may have caused a conflict I uninstalled Works and am still having the problem. In addition I have been using the W2K auto update and have installed SP3. Any idea of what I can do to resolve this?