If SQL doesn't start it will tell you why in the Windows event viewer, if a DB doesn't start it will be in the SQL error log.

As Perry has already detailed the logs are typically stored where the binaries are but can be changed.

As for auditing it all depends on what you want to audit, maybe here will be a good place to start reading up http://msdn.microsoft.com/en-us/library/cc280386%28v=sql.105%29.aspx or do a search on a search engine of your choice on the topic