Since my friend Hank "loaned" me his laptop a few months ago, my life has gotten much simpler.
I just use Microsoft Word to display the lyrics. You can enter the Artist, Title, Genre, etc., and call them up as you wish.
Then just open the file and the lyrics are displayed in Word.
Use a type face that is readable, and large enough to see, and still fit all the words on one page.
I change the "View" in MSWord to "Full Screen".
I have a quite large collection of lyrics, with chord names. It has taken years of accumulation and countless hours of work but I finally have most of them converted to computer.
I don't try to display any scores, but it should work the same way.
I think also that there are dedicated programs for this, but I don't have one.
My one Christmas present this year was a wireless mouse, and that helps.
DonM