Windows XP Update fails because it is missing Automatic updates service / Automatic update service will not start.
I came accross this when working on a customers machine.
The first thing you will want to do is download the latest version of Dail-a-fix. Run the windows update and MSI fixer. Next you should open a command prompt by hitting: START – run – "cmd". In the command box window type:
This will re-register this service.
EXTRA NOTE – An inplace repair install of XP will not correct this issue.