I have some update or something that tries to run every night, and ends up leaving the SQL Server service stopped. When the machine restarts, the service restarts properly. How do I go about diagnosing and fixing what is breaking my SQL Server service? I'm running SQL 2005 on Vista Business.
First look in the event viewer to see if there is more information about why the service isn't starting, or to see exactly when it gets stopped.
We've had this issue with SQL Server 2005 on our dev server. What was happening in our scenario was that the user account under which automatic updates were running wasn't a local machine admin. Automatic updates were in the queue, the machine tried to apply them to SQL 2005, was able to shut down the service but never restarted it after failing to apply the patches.
This may not be your scenario, but the symptoms sound similar. Event log entries? (They were the telltale for us; we Googled the message and found out about the auto updates.)
Check the event log and the sql server error log. They should provide you with hints or the actual error so you can fix it.