Windows Vista Service Pack 1 might very well deliver users from the Reduced Functionality Mode black screen of death kill switch, but the prerequisite updates for the service pack are doing a wonderful job at cutting access to the operating system. Following Microsoft's monthly patch cycle non-security updates released on February 12, 2007, containing two of the remaining prerequisite updates for Vista SP1, Vista users began complaining about installation failures. Some Vista machines, after the implementation of updates via Automatic Updates are thrown in an infinite reboot loop, while stuck on displaying the following message: "Configuring Updates Stage 3 of 3 0% complete. Do not turn off Computer."
The number of user complaints on the TechNet forum for Windows Vista Service Pack 1 (SP1) under the thread “Configuring updates: stage 3 of 3 stuck in endless reboot loop”, as well as the “Stage 3 of 3 - 0% then reboots” thread is growing in consistency. But Microsoft is saying little to almost nothing on the subject. It is still unclear at this point in time if the users affected by the infinite reboot loop have also attempted to deploy Vista SP1 RC refresh 2 or RTM builds. However, all of them had the machines configured to deploy updates automatically via AU. Speculations are pointing to a conflict between some of the updates, specifically the prerequisites for Vista SP1 and security solutions installed on the computers. The most facile solution to date involves using System Restore, the details are available here.