Help with Vista resetting personal preferences on each system rest

I have an HP with Vista Home Premium installed with SP1. It automatically
downloads updates. I am the only user & person with access and there is only
my account on the computer under my name so it show to be the sole
administrator.

Every time the system restarts or reboots my preferences are lost (including
system self reboots when updates are applied). The Start Menu reverts from
Classic which I prefer, to the default. Personal preferences for installed
progams like games are removed so I continually get a pop up to accept them
each time I want to play them, even though I go through the routine of adding
them as accepted.

I need some help as to determine what is causing this and how to fix the
problem.