If PageDown key does not work in MS Word Print Preview mode
How strange! PageUp works just fine when you browse your document in Print Preview mode at Microsoft Word, but not the PageDown key. You are still able to move forward only by pressing Ctrl+PageDown, but you don’t want to use a shortcut when you can press just one key.
Your keyboard is (most probably) fine, and you don’t need to adjust any Word settings — just try to increase the size of Word. Put the cursor of the mouse at a corner and drag to increase the window of Word.
This PageDown problem is caused when the pages are a little larger than they should be.
Instead of enlarging the Word window you can also open the Zoom settings and make the preview pages smaller. Enjoy!