Desktop computers?
I still have my slide rule from high school.
Our cell phones will probably replace desktops and even laptops.
All you need is a phone dock to connect a large monitor and everything that goes with personal computing.
I saw a demonstration video of a concept Iphone, where the Iphone could project a 10 inch holographic screen and it could also project a virtual keyboard to type on.
Those were working prototypess too. The only problem is getting how much power it uses down and getting the battery power up.