help appreciated
help and support works fine except for one nagging
problem index has disappeared but

This seems to be a common problem with no definitive resolution.
In most cases it was caused by a security update from windows.

Here are 2 sites that have fixes that many claim haven't resolved this issue, but worth a look at to try yourself.
Seems the worst case senario is to reinstall Help & Support (instructions at the kelly's korner link)

Good Luck!

Why doesn't Help and Support work?

Win XP Fixes: Fix Windows XP Help

One last tip I saw was the following, tho i have tried it myself and got no response:

Go to Start/Run and type in: helpctr -regserver

many thanks for advice,will try and let you know result of correct fix/s
cheers