Thanks.

I can open studio manager but when I try to connect to server it fails with

TITLE: Connect to Server
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Cannot connect to (local).

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ADDITIONAL INFORMATION:

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 2)

For help, click: http://go.microsoft.com/fwlink?ProdName … nkId=20476

The advice I have obtained suggests that the solution may vary depending exactly which version of Sql Server you are using.  If you can let me know this then we can look into it further.

These seem to be the most comprehensive instructions

http://www.mytechmantra.com/learnsqlser … _2008.html

also

http://blogs.msdn.com/b/psssql/archive/ … -2008.aspx

There are two setup commands: one in RELEASE and the other in SQLSERVER2008R2.  Since I am running SQL Server 2008 R2, I consider the latter to be more appropriate but have been using both.

I am still unsure what value I should be using for the parameter /SQLSYSADMINACCOUNTS= accounts

I have used
ADMINISTRATOR
sa
“DerekCOLEMAN-PC/Derek Coleman” (my username in the connect to server window)
“Derek Coleman”

When trying setup from RELEASE for the above four accounts, I get same the error messages

Final result:                  Failed: see details below
Exit code (Decimal):           -2068643838
Exit facility code:            1203
Exit error code:               2

Exception type: Microsoft.SqlServer.Setup.Chainer.Workflow.NoopWorkflowException

Message:
The state of your SQL Server installation was not changed after the setup execution.

I have found one blog
http://blogs.msdn.com/b/psssql/archive/ … -2008.aspx
which suggests this error is because master.mdf does not exist in
C:\Program Files\Microsoft SQL Server\MSSQL10.MSSQLSERVER\MSSQL\Binn\Templates
however it does

When trying setup from SQLServer2008R2 for the above four accounts, I get same the error messages

Final result:                  Failed: see details below
Exit code (Decimal):           1152035024
Exit facility code:            1194
Exit error code:               43216
Exit message:                  Exception has been thrown by the target of an invocation.

Inner exception type: System.ArgumentNullException
Message:
                Value cannot be null.
                Parameter name: InstallMediaPath.

There is no parameter InstallMediaPath on the setup command so presumably is called elsewhere.

I also tried deleting the corrupt master, model, msdb data and log files in
C:\Program Files\Microsoft SQL Server\MSSQL10.50MSSQLSERVER\MSSQL\DATA
and replacing them with the files in
C:\Program Files\Microsoft SQL Server\MSSQL10.50MSSQLSERVER\MSSQL\Binn\Templates
then opening SQL Server Management Studio and connecting to server but this failed.

Please that you have got it running again. It could be that Server Objects/Backup devices are part of the Master database, which is why you have lost backup. Otherwise Recorder doesn't modify the Master Database and certainly doesn't write to it during normal operation.  Agent isn't running on my machine, but browser is.

For the record  from what I can see SQLSYSADMINACCOUNTS= DerekCOLEMAN-PC\Derek Coleman would be correct although  I have read that if you installed using mixed mode then you also have to provide  the sa password for the repair. SQLSYSADMINACCOUNTS= DerekCOLEMAN-PC\Derek Coleman/SAPWD=r2k.

Also if  there are other  instances of SQL Server installed elsewhere which use exactly  the same version of SQL SERVER then  you can use  a backup from there to restore the master.  It appears that you have done something on these lines.