This also happen to me just recently, looking for solutions, the work around I found was to disable the TCP setting and go with name pipe. Not the best solution but works. I would like to go back to TCP/IP but when ever I enable the setting and restart SQL I get the following errors:

* Event Time: 10/6/2008 10:05:10 AM

* MSSQLSERVER Error Event

* Event ID: 17182

* TDSSNIClient initialization failed with error 0x2740, status code 0xa.

* Event Time: 10/6/2008 10:05:10 AM

* MSSQLSERVER Error Event

* Event ID: 17182

* TDSSNIClient initialization failed with error 0x2740, status code 0x1.

* Event Time: 10/6/2008 10:05:10 AM

* MSSQLSERVER Error Event

* Event ID: 17826

* Could not start the network library becasue of an internal error in the network library.

To determine the cause, review the errors immediately proceding this one in the error log.

* Event Time: 10/6/2008 10:05:10 AM

* MSSQLSERVER Error Event

* Event ID: 17120

* SQL Server could not spawn FRunCM thread. Check the SQL Server error log and the Windows event logs for information about possible related problems.

Need help other then reinstalling SQL....

Thanks,

Aaron