Why does my Samsung Galaxy S3 keep crashing apps and Internet pages?

A

AC Question

I have an S3 which 1 year and a half old and for the past few months, every time I want to read something online or to play a game, it keeps crashing and returning to the main menu of the phone. At first it was occasional, but now it's starting to happen every single time. What can it be and is there something I could/should do?