svchost.exe 100% CPU when using Windows Update

Here is the situation: PC dating back to around 2003 running Windows XP SP2 in need of general clear-out and tune-up with all software to be updated. Automatic updates were not working and using Windows Update online would not work at all. Had to download standalone installation of SP3 and install, which all went smoothly. Using online Windows Update now seems compatible, but PC becomes unresponsive and process svchost.exe found to be using 100% CPU. Looking for help online I only found old patches that are included in SP3 anyway. Time to get inventive! Using my trusty old copy of Dialafix tried clearing out Software Distribution folder, but preserving DataStore.edb (update history). That did not resolve the problem. Once again using Dialafix cleared out DataStore.edb as well. Problem solved. The only data lost in this exercise was the Windows update history, which is nothing to cry about! It simply means that Windows Update will have to rebuild that file next time that updates are applied.