A. A. SQL Server uses the following registry keys. (If you delete all these then the SQL setup routine shouldn't spot the old version)

All versions

  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSSQLServer
  • HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSSQLServer

6.0 and above.

  • HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSDTC
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SQLExecutive

7.0 and above

  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SQLServerAgent
  • HKEY_LOCAL_MACHINE\Software\Microsoft\Microsoft SQL Server 7
  • HKEY_LOCAL_MACHINE\Software\Microsoft\MSSQLServ65