Notepad freezes on startup
As many users reported, this is caused by the LightExplorer plugin. One way out is to just remove LightExplorer.dll from the plugin folder, or to change its extension to something else than .dll. This gets Notepad++ to display normally, bu without the functionality of the disabled plugin.
There is a way to have the cake while eating it: in the administrative tools, go to Windows services, and enable LanmanServer. With this adjustment, LightExplorer no longer prevents Notepad++ from showing up and functioning normally.
This issue has never been reported under XP.