If you want to delete a service in Windows 2003 or 2008 then run the following command.
sc delete <service name>
Refer to the following website for more details.
If you are looking for info on PSSDIAG for SQL Server then please continue reading.
How to delete PSSDIAG service in Windows?
If you have recently opened a ticket with Microsoft regarding a SQL Server issue then you will be aware that they will ask you to run a diagnostics tool called PSSDIAG.
There are some caveats to running this tool.
1) Make sure that you limit the size of the files that are created using this tool. Mention this to Microsoft and they will customize the PSSDIAG for you.
2) Always run this as a service and not as a SQL Server agent job or on the command line. Otherwise it will not shutdown properly and you won't capture what is required.
3) Check the file size after an hour to make sure that will not keep growing.
4) Create the service as 'pssdiag.exe /R'
5) Start the service as 'pssdiag.exe START'
6) If you stop the service using the command 'pssdiag.exe stop' then wait for a few minutes before executing the stop command again.
7) You can stop the service using 'pssdiag.exe STOP'
Finally when you are done with the ticket uninstall the service using the following command
sc delete PSSDIAG