Press Windows + R key, input msconfig, and hit "Enter" to open the System Configuration utility.
Verify General and Boot tab look something like these
[image|3423606]
[image|3423610]
If they do, then there might be an HDD/SSD or CMOS issue.
I would start by booting with a Windows USB thumb drive and doing a repair install.
You can create the thumb drive by downloading a Windows version here
https://www.microsoft.com/software-download/
Select an option to download and create a USB drive.