Trying to install MOM 2005 on a test 2003 Server only to receive the error message "SQL Server 2000 SP3 or later not detected".
Because I have SQL 2000 SP4 installed as an upgrade of an earlier MSDE incidence (and it seems MOM 2005 install does not detect SQL 2000 SP4 correctly) I had to temporarily change the following reg key:
HKLM\SOFTWARE\Microsoft\Microsoft SQL Server\MSDE\MSSQLServer\CurrentVersion"
CSDVersion REG_SZ change from "8.00.2039" to "8.00.761"
Do not be confused by the MSDE term - This was what the incidence was called before being upgraded to SQL Server 2000.
Don't forget to change it back!