Thanks Dan. Will do.
I tried uninstalling both the normal way (Control Panel|Programs) and using the Microsoft Fixit link you gave me. No difference.
Interesting, though. When I log in as Admin (where I installed VM the last time only - usually I do it as myself) I get the categories etc. But not when I log in as myself. Is it something to do with the fact that I keep my calendar data on the D: drive rather than in the default place? By why should it have changed after the crash?