Win2k problem ???

We’re using Windows 2000 Pro and Server. One of the Win2k Pro machines has developed an interesting problem. When you click on Start, nothing happens. The button stays down, but it does not function beyond changing that graphic to look like it isdown. We have the alternative of running executable programs from desktop shortcuts, but we shouldn’t have to do this. Does anyone know what is going on here? The user has no problem with other 2k machines, just this one — so it shouldn’t be a profile issue. Anyone seen this before? Anyone have a solution instead of a work-around? Preferably not a reinstall.