SQL Services wont start from the Services manager

Issue
In a recent DR scenario, a SQL2000 server was restored from tape backup.  As expected, the flat file backup succeeded but databases were not available and had to be restored from last known good database backup to disk.

I completed the master database restore by starting the SQL Server in single user mode from cmd (using sqlservr.exe) and wanted to restore the rest of the databases afterwards.  I could not start SQL Server using services console, error reported was reported in the eventlog, but not SQL Server errorlog.
The MSSQLSERVER service failed to start due to the following error:
The system cannot find the path specified.

Diagnostics

I could start the service using cmd (sqlservr.exe) so it appeared that something was wrong with the service and where it was pointing to attempt to start sqlservr.exe. 
Also confirming this was the fact that there was no new SQL error log written, indicating that it wasn't finding sqlservr.exe to attempt to start the service.

Fix

The windows engineer had a look and modified the registry for the path of the service (to sqlservr.exe).  Once completed, the services could be started/stopped from services management console.