Using the command line, how can I undo the last installed windows updates?
Windows Updates should create a System Restore Point before installing the update, so you should be able to roll back to that.
How to restore Windows XP to a previous state describes the steps to rollback to a restore point and although is obviously Windows XP specific, the process should be similar for Server 2003.
Note that you can launch the System Restore GUI from a command prompt
but I'm not sure if it's possible to execute an actual restore this way.
You could use wuinstall. It is a command line tool for managing Windows updates. Although there is no explicit command for undoing the last update, you can uninstall updates in several ways. The basic command is:
There are many ways to select the updates to be uninstalled. For example:
The command for uninstalling an update with a known KB number would be:
For more info, see here.