Re: Keyboard Shortcuts for Page Up/Page Down not working

@LolaLikesC4  Are you playing Sims 3 or Sims 4?  (This is the TS3 section, but your post history suggests TS4.)  In either game though, the first step to try is the same.  Remove your entire Sims 3/4 game folder from Documents\Electronic Arts, launch the game to create a new folder, start a random save, and see whether page up and page down work now.  If so, you can move your saves and other content from the old folder into the new one.

If this doesn't help, did you happen to change your default keyboard layout recently?  Some non-English keyboards don't have all the right key bindings, for whatever reason.