There are lots of method to take a snapshot of computer screen.I will show you easiest method.
(1)Press "prntscr" (you have to press it with fn(functiom) key in laptop).
(2)Now,opne paint and paste it(ctrl+v).
(3)Choose your size and save it with jpg extension.
Now easiest method is.....just press windows+prntscr.It will save your computer screen's snapshot,But it will in png extension.If you want it in jpg format,rename it with jpg extension.
