What a tortuous saga. I've sworn long and loud over all the misfortunes listed above in agitated ignorance that I wasn't the sole innocent adrift in a sea of absolutely insoluble snags. I'd tried the Registry approach after advice by an IT manager to delete any key with Adobe in it. This seriously reduced the effectiveness of XP as many functions stopped work. Fortunately there was only one key I'd deleted and normal service was resumed swiftly. I thought relief was at hand when thanks to this string I learned of the Installer Cleaner No joy tho'. I've spent days on this task and it is ironic that all I wanted was to refer to the manual for my printer to see how to clean the heads of the ink cartridges as the colour one had stopped working; this manual is in Adobe PDF format. Fortunately today I found from Wikipedia how to do it with some distilled water and a paper tissue to discover my spare was empty as almost was the working one. An almost total waste of time but good experience.