Restore the SQL Server master database?
Please see http:// techrepublic.com.com /5102-6268-5025441 . html for more details.
Also, be certain that when you put the MSSQL server into single user mode that you connect quickly using query analyzer (using Windows authentication) before the connection is utilized by another program or user.
Otherwise, you’ll have to stop and start it in single user mode, and attempt again.