Convert Chrome icons to PDF forever [Closed]

Registration date
Monday July 17, 2017
Last seen
July 17, 2017
My all PDF icons has changed to chrome. I know how to open it with with reader by choosing default opening as reader but the problem is that when I restart my computer. All icons have changed to chrome again, everytime I open my PC , I have to change chrome icons to READER again. It's so headache to reset them every time I open my PC, PLEASE tell me a solution so that I don't have to change all icons on every startup.

P.S: I have window 8.1