This one puzzles me. PgUp and PgDn regularly stop functioning on this laptop (Dell Latitude 7400 with Win10, 2 years old and otherwise in good physical condition).
I'd immediately suspect a hardware issue, however there also regularly are periods where these two work just fine (like right now). For as far as I can tell I haven't installed anything that intercepts or alters keystrokes, and it doesn't seem like a StickyKeys issue (I disable that every time I get a new laptop or OS). Sometimes pressing one of them for a while seems to get them going again (although sometimes also not), and if one works, both do, and if one doesn't, neither do.
Before I raise a support ticket and go into a lengthy keyboard replacement process, are there any OS or software related causes for this, that I may have overlooked? Any further diagnostic suggestions are also welcome. Thanks!