Unable to establish connection to database.

• Error information:
  Microsoft OLE DB Provider for SQL Server (0x80004005)
  [DBNETLIB][ConnectionOpen (Connect()).]SQL Server does not exist or access denied.
• Other possible cause of this problem:
  The database cannot be opened, most likely due to incorrect connection settings or insufficient security set on your database folder or file.
  For more details please refer to http://support.microsoft.com/default.aspx?scid=kb;en-us;Q306518