After being in Insider Preview for so many months, finally it is the day, The Big Day, July 29th when Microsoft said to roll out something big. As stated earlier, Microsoft has already started rolling out Windows 10 Free Upgrade for PCs Reserved via Windows 10 App.
If you have already reserved using Windows 10 app on your PCs or Laptops, you must need to go and check it right away. Make sure your system is connected to internet properly. The Windows 10 update will start downloading itself automatically, you dont need to do anything. Download size of Windows 10 (64bit) is around 2,713.8 MB. So make sure you are not connected via Mobile 3G/4G.
As mentioned earlier, Windows 10 Download will run in background, once it is completed, the App will let you know to Restart the PC so that your current Windows 7 / 8.1 PC can be upgraded to all new Windows 10. Have a Happy PCing.