Autohide the taskbar question?

Suddenly, I cannot get the autohide function to hold. When I check this option and apply it, then click ok it disappears just like it is supposed to.When I move my cursor to have it appear again, she shows up correctly.When I move my cursor to another location the autohide no longer has any effect. The only way it will hide is if I uncheck that option, apply it, click ok and then go through the whole procedure again of rechecking it, clicking ok and closing.In the past I have seen this happen intermittently but very seldom. It seems to be permanent at the moment.Any ideas?Thanks:RTH