Help with adjusting 192 DPI to a smaller DPI

I was trying to assist an older friend in adjusting the size of what he sees on his computer. Went to the "Personalization" page, "adjust size and color...". Went to the "scale" and adjusted to the DPI of 192. Clicked on "apply", restarted the computer, and the adjustment was made. The problem is that the 192-sized DPI helps him to see what's on the screen, but shifts the way that pages and icons appear. Things that would normally appear on 1 page no longer do so that you can't find things that you need on a page. I've tried to change the DPI back, but no "ok" button shows up on the new DPI-sized page so when I choose a different smaller sized DPI I can't get it to lock in and it defaults to the 192-sized DPI.

I hope someone understands my problem and can help. Thank-you in advance for your assistance.