Keywords:
Windows Installer error 1920
Service Control Manager error
Service Control Manager hangs while loading service
Could not start [service name] on the local computer.
Error 1053: The service did not respond to the start or control request in a timely fashion.

If you are using the ServiceBase class from the .NET library, and also set the CanHandleSessionChangeEvent = true, your service will hang during load under Windows 2000.

I have not seen this confirmed anywhere else, but I've proven it to my own satisfaction.
Interestingly, you don't need to call the base.OnSessionChange(changeDescription) to get it to fail, simply setting the property is enough to bork your service under Windows 2000.

Solution
The solution is obvious … don’t set the CanHandleSessionChangeEvent = true if you are running under Windows 2000.