Thank you GG.
It seems to be an interesting utility but from what I can glean from the MS 'Geekspeak' it doesn't do what I need - stop these partial appearances of the Windows Installer operating boxes. They don't appear to be causing any obvious damage and, on balance, I think I will leave well alone and put up with yet another of Redmond's oddities!

Apropos of which, this is being sent via Konqueror in Suse 9. What an extraordinarily simple, straightforward method of internet browsing etc. This is my first time of use and what a revelation.... clever chap that Mr Torvalds.