If you are having failures to install Security Update for Microsoft .NET Framework, Version 2.0 (KB917283) Go to click here and download the "dotnetfx_cleanup_tool", about 13 lines down. Unzip and run it, and use the spin box to remove Microsoft .NET Framework 2.0. Leave version 1 alone. After it uninstalls and reboots, go to Windows Update and it will show that Microsoft .NET Framework 2.0 needs to be installed. After that, search for updates and the update for it (KB917283) will install correctly.
Stuartli Thanks for that but I together with lots of others just used Windows Update and took what came. I don't remember when I updated from 1.1 to 2 but obviously as time went by it got corrupted and so caused the problem. Although there are 3 files to download it isn't apparent to me which one to use (not that I need to now) but it might be useful for others to determine how to choose.