From the Real World: SQL Server 2000 SP4 Installation Failure
March 4, 2009[From SQL Server Central]
In this article I want to show you one tricky issue I faced recently. This took around 6 hours to track down what exactly was happening and hence I am sharing the details so that if you have the same problem it will be a quick check for you instead of hours.
My client environment is not totally upgraded to SQL Server 2005, and I still have a few SQL Server 2000 servers in my environment. On one such SQL Server 2000 server I received the request to install SP4. SP4, which is usually a cakewalk to install, failed.
The article continues at http://www.sqlservercentral.com/articles/SQL+Server+2000/65563/