Let me summarize the answers for others' benefit (for python and notepad++)
1) Ctrl+K on multiple lines (i.e. selected region) allows you to block comment.
Also note that pressing the combination multiple times allows you to add multiple "#"s (sometimes I use that while testing to differentiate from other comments)
2) Ctrl+Shift+K (on the commented region) allows you to perform block uncomment
3) Ctrl+Shift+K on an uncommented selected region does not comment it
4) Ctrl+Q allows you to block comment/uncomment in a toggled mode (meaning, you cannot add multiple '#'s like in 1) )
Hope this helps another wandering soul.
Question - how would you develop a hack of keyboard combinations to comment/uncomment if there were no shortcuts? Just curious. I've no clue hence asking.
Without having selected a language type for your file there are no styles defined. Comment and block comment are language specific style preferences. If that's a PITA...
To add a comment under any code on NOTEPAD++ first we have to save and define the programming or scripting file type. Like, save the file as xml, html etc. Once the file is saved in proper format you will be able to add a comment directly using the shortcut ctrl+Q