Solved! No bootable device.

[jnsackitey]

My Toshiba c55 is displaying "no bootable device. Please, restart your system.
I've changed the boot order and made the HDD first, but it still appears. It's a Windows 10.
And I don't have the original setup.

What do I do now please?

 

[Saga Lout]

It could be a hard drive problem. If you power on and off a few times, it should force Windows 10 to offer you StartUp Repair options, if the system lets it go that far.

The alternative would be to removed the hard disk and slave it to another machine using a cheap cable and connector. Running Checkdisk with the /r switch and the sfc /scannow command to fix or replace corrupted system files.

 

[jnsackitey]

Thank you.
But I don't understand the steps for the chekdisk

 

[Saga Lout]

At the Command Prompt, type
chkdsk c: /r
that invokes Checkdisk to run on your C:\ drive and the /r switch is to repair any errors it finds on that area of the disk.