Just about every computer produced in the past ten years is capable of doing most everyday tasks online such as web browsing, email, music, videos, pictures and documents. Unfortunately most of those computers came with Windows XP, Vista, etc.
One can install any Linux distribution they choose, however to really revive an old PC, using a lightweight variant of Linux is really the best way to go. The fewer hardware resources the system needs, the better the 'ol girl' will run and will negate any idea that old hardware is useless.
Now given where this article is being published, of course LXLE Linux will be mentioned as a great full featured lightweight drop in and go operating system for your old XP/Vista box, but there are many amazingly great lightweight distributions to choose from like Lubuntu, Crunchbang, Zorin Lite, Linux Lite, Puppy Linux or Watt OS, just to name few.