Moving away from XP
Part way solution to removing vunerable XP installations. MS could give away free the Windows 7 Starter Edition (subject to a registration process). It will run on older hardware allbeit slowly but its better that then a compromised PC. This would cut down piracy and hacked versions, if legitimate downloads & product keys could be aquired from MS directly. This seems a better solution to me than the advice from MS to buy a new PC, as not everyone can afford to do so.