Thanks for that John, though I have no qualms about doing a completely clean install of W7, I often have a clear out of the system when things become a little congested!, it is nice to know that it can be done as you say. My only concerns are compatibility of my present software,printer and scanner drivers for example. When I upped to Vista 64bit I had to scrap my Zone Alarm Pro and go for AVG Internet Security because ZA had not caught up with 64bit! John.