I tried the apropos.exe fix with no joy. Guess I didn't have that piece of spyware - but I still had the problem.
A friend of mine - who had the same problems - pointed me here (on this site):
http://www.annoyances.org/exec/forum/winxp/1134095035
Suggestion #5 - Uninstalling Microsoft Windows Update 905749 worked for us.
Good luck all.