I tried to use Windows Update (WU) this last weekend to install Vista SP1 on my PC. Got error 80072F78. When I googled the error message the responses I read suggested that either the date and time were off; not the case; or that I should shutdown any unnecessary processes running in the background. I don’t want to shut down my firewall or AV programs. I will just try redownloading the update again and see what happens. – The error message changed to 80200010 – The web suggests deactivating all of “Norton” type products. Again, I don’t want to shut down certain programs. – The third time appears to have been the charm. SP1 is now loaded and everything ‘appears’ to be working fine. – Update, the Search function seems to be missing from the start menu, but since it is in several other locations that is not an issue.