August 1st, 2015, 13:42
I grabbed the Windows 10 ISO for 64-bit Home version from the site Ickie posted. Burned a DVD. Note that Windows 10 will give you a new Product Key... different than your old key from Windows 7 or 8.1. I used a utility named ProduKey to get the key from my computer, after the update:
If you burn a DVD, write your Product key on it so you don't forget... all of this just in case of the possibility of a harddrive crash, you might not have to buy windows 10 for the new drive. It happens.