regrebld is a utility that you can use to back up and restore the SQL Server Registry entries. It creates a set of files in the \Microsoft SQL Server\Mssql\Binn directory with the .RBK extension. The syntax is as follows :
regrebld [-Backup -Restore ]
You can run regrebld with -Backup to back up the Registry settings or use the -Restore option to restore the Registry settings and verify the state of SQL Server services.
A recommended alternative to running regrebld is to run the SQL Server 2000 setup program, select the Advanced Options button on the Installation Selection screen, and then select Registry Rebuild on the Advanced Options screen.
The regrebld utility is not installed as part of the SQL Server 2000 installation, but it can be copied from the installation disc.