Hi Peggy,
Are you referring to adding PreferLegacyPrintDialog in the registry? If so, it appears this method for restoring the legacy print dialog only works with a few applications. I tested several apps, and it still works in modern Notepad, but it no longer seems to work in browsers.
If you want to open the legacy print dialog in browsers, you can press Ctrl + Shift + P. Aside from the method above, there doesn’t seem to be another way to restore it, unfortunately.