I'm at a customer's place and his comp couldn't access the Microsoft Windows Update web site. It would just report that there is an error and cannot run. I tried many techaniques from re-installing Windows Installer 3.1 (v2) to Internet Explorer 7 (which failed to install) to checking cryptographic services. Finally, my persistence paid off! I found this Microsoft article, http://update.microsoft.com/windowsupdate/v6/showarticle.aspx?articleid=76&ln=en&IsMu=False , which explained that the SoftwareDistribution folder needed to be purged. I did what it said and PRESTO! The MS Windows Update site is now working. I'm downloading & installing 91 updates for the customer. PHEW! It wasn't looking good to the customer and I was afraid I might have to do an in-place re-installation.