how i install windows from iso ? can i download setup from internet?

you mean i reinstall windows 10 on my laptop ? and what is gwx?

ok i will try this and will you please tell me how to activate windows .. as when i bought laptop then this "activate windows" not appear on windows 8 so when i upgrade to windows 10 this is displayed

previously i have windows 8.1 when i bought laptop then windows show notification upgrade it windows 10 so i upgrade it but windows not activate so when i go to settings - update and security ......