Hey there, starworld.
The way the upgrade happens is the following - download Windows 10 and it will sit dormant on your PC until its official release date (July 29th). When the day comes, you'll be prompted to upgrade and that's it. Having in mind you've already downloaded the file, the failed Windows 8.1 update should have nothing to with this and the installation/upgrade of Windows 10 should go without a hitch.
Hope that helps.
Boogieman_WD