It worked on my XP laptop for a time, but it seemed to stop, by which I mean that at intervals of one or two months, I would check for updates and would be told that none were available. From time to time it would say a new version of Microsoft Malware Removal Tool was available. I guess it could simply have been that there weren't any other updates. When the Windows 10 insider programs was clearly going to continue after July 29, I did a full install. i still have the Dell restore disk for XP SP3 if I ever want to go back, which I very much doubt will ever happen.