Screen auto rotation in Dell inspiron 13 7348.

I brought 13-7348 just now. initially auto rotation worked and later it is not working.

i tried 

but it is not working.. can you please help me this..

one more in system configuration (Windows+R -->msconfig)- in general tab, i have been selecting normal start up and when i restarting it is changing to selective startup. what needs to be done to resolve??