Microsoft now lets users of Windows 8.1 and Windows 7 decline the free Windows 10 upgrade offer, with the click of a button.

When you see the Windows 10 upgrade prompt, you will see 3 buttons:

  1. Upgrade now
  2. Choose time
  3. Decline free offer.

Click on the Decline free offer link, and Microsoft will stop bothering you to upgrade to Windows 10.