How can I restore my backup to my Windows 10 computer? Is the file corrupted, if so, how can I fix that?

I had to send my computer to HP to fix one of my USB ports. They told me to back up my computer because they would have to factory reset it. called Microsoft to help me do this. they had me do an image back up which took FOREVER. I backed up my ENTIRE computer. I dozed off a minute and the computer ended up going to sleep. I can't restore any of my information. Files, programs, history, pictures, documents, passwords, etc. All gone. My back up took HOURS to complete. If I could guestimate, I would say around 5 hours. My computer is not recognizing the file that was backed up to my external hard drive. I see the file, but it acts if it's empty. but when I click properties and size. there is a gigantic amount of space used. MS said if the file probably corrupted from when the computer fell asleep, (Nobody warned me of this happening.) Is there anyway possible to restore my computer with my external backup? I've tried just about everything so far.