Delete Lines containing specific keyword or multiple keywords using Notepad ++

Goto the search menu Ctrl+F and there to the "Mark" tab. 

Check "Bookmarkline" (if there is no "Mark" tab update to the current version).

Then just enter your search term and click "Mark All"

All line containing the search term are bookmarked.

Now go to the Menu "Search -> Bookmark -> Remove Bookmarked lines"

Done.