Don't know if I understand your question. You want to install SP3 on Windows
2000 SP4 box ? You can uninstall SP4 from Add/Remove programs and then
reapply SP3.
The password in console is the password you supplied during AD installation.
This is basically your DSRM password. When you boot in console you are not
starting AD, so you must supply a local Admin password that was set during
DC creation. For LSASS.EXE try searching Google as there are some
possibilities about this. If you start your server in Safe mode, do you
experience the same problem with lsass.exe ?