Which installation did you brought?
To repair a current Windows installation, you need a bootable USB.
If you have another PC:
- Download the following tool:
Download tool now (microsoft.com)
- Insert a blank USB with at least 4 to 8 GB of space in it.
- Run the tool and choose Create an installation medium for another PC.
- Select the correct USB.
- Let the process finish. Make sure you don't turn off the PC or remove the USB.
When done:
- Insert the USB into the affected PC.
- Turn on the PC.
- Immediately, hold down the boto key of your PC. It's mostly F12, F10, Delete or some special key. You can search for it on the internet.
- Select the USB drive and press Enter to boot from it.
In the Windows 10 installation environment:
- Click on Next.
- Click on Repair this computer and wait for some time.
- Click on Troubleshoot > Advanced Options > Startup repair.
- Let the repair finish. Do not interrupt it.
If the startup repair failed:
- Go to Troubleshoot > Advanced Options > System Restore (this will work only if you have a system restore point)
- Select the latest point and restore from it.
Regards,