There are three options you have:

1. Erase Windows 10 and install Windows 8 or 8.1 again
2. Try to fix the new upgrade installation
3. Try to reinstall the Windows 10 upgrade

Unfortunately, this is the best option of them all, as if your computer failed the update, it is most probably not fully compatible with the new operating system and whatever else you will try to do, it will always fail.

You can try to fix the upgrade by going to the manufacturers website of you laptop/PC and try to find a solution for the problem.

The majority of manufacturers have pages and pages of information on the new operating system and in some cases actually have found solutions for your problem.

You can try to reinstall the update as long as your computer is still running.

If it's not and you have not saved the download of the new operating system update, you have no other option then option 1.

If all of the above have failed you, or you simply are not confident enough to apply these solutions, just drop the laptop/PC into our workshop and we will be able to help you most probably the same day.