SQL Server 2005 Configuration manager services list empty

Most likely you need to re-register the SSRS WMI Namespace and/or the WMI Provider. You can troubleshoot and fix the problem using the following steps.

Troubleshoot the problem using the WMI Tester

1. Close all instances of Reporting Services Configuration Manager or SQL Server Management Studio.
2. Open a command prompt and type wbemtest, and then click OK.
3. Click Connect in the WBEM tester dialog box
4. In the Namespace field, type the following string, and then click Connect. root\microsoft\sqlserver\reportserver \v9
5. The namespace you specify should appear in the WMI Tester dialog box. If you see an error message instead, the WMI namespace for Reporting Services is not registered correctly. To resolve this issue, follow the procedures later in this article for registering the WMI namespace for Reporting Services.
6. Click Enum Classes, and click OK in the Superclass Info window.
7. In Top-level classes list of the Query Result window, double-click the MSReportServer_Instance class.
8. Click the Instances button. You should see a Query Result window that shows all the instances of Report Server on your computer. If not, the Reporting Services WMI provider is not communicating with Reporting Services Configuration Manager or SQL Server Management Studio. To resolve this issue, follow the procedures later in this article for registering the Reporting Services WMI provider.
9. If you successfully resolved the issues in the WMI Tester dialog box, restart Reporting Services Configuration Manager or SQL Server Management Studio to determine whether that the error is resolved.

Repairing Report Services WMI Provider

1. Close all instances of Reporting Services Configuration Manager or SQL Server Management Studio.
2. Open a command prompt.
3. Add the class instance of the Reporting Services WMI provider to the WMI repository. In the command prompt, run the following command:
   mofcomp "%ProgramFiles%\Microsoft SQL Server\90\Shared\reportingservices.mof"
4. Run the WMI Tester again to see whether you can now connect to the namespace for the Reporting Services WMI provider and continue with the debugging process.

Register the Reporting Services WMI provider

1. Close all instances of Reporting Services Configuration Manager or SQL Server Management Studio.
2. Open a command prompt.
3. Register the Reporting Services WMI provider. In the command prompt, run the following command:
   regsvr32 "C:\Program Files\Microsoft SQL Server\90\Shared\reportingserviceswmi.dll
4. Run the WMI Tester again to see whether you can now connect to the namespace for the Reporting Services WMI provider and continue with the debugging process.

Here is the source for this information, Microsoft's How-To on troubleshooting WMI Provider errors in SSRS.

It looks like this site has some troubleshooting steps you can try:

http://blogs.msdn.com/sqlserverfaq/archive/2009/06/12/unable-to-start-sql-server-agent.aspx