Boot device not found

[Dasia1]

The boot device is not found on my winds 10 laptop, and it tells me to install an operating system. I was restarting my computer, and then all of a sudde this showed up and I can't see any other screen. I don't know what to do

[WAWood]

@Dasia1 

This issue is often due to a failing drive. So, let's check that first, because if it is failing, it would need to be replaced and there is no point then in doing anything else until we confirm that.

If your PC is new enough to support UEFI, you can use these steps to test the hard drive: http://support.hp.com/us-en/document/c00439024

If not, to check the drive you have to follow these steps:
1) Press Esc key repeatedly, several times a second, while rebooting the laptop. Do NOT hold the key down, just press it over and over.
2) Eventually, you will see an HP Startup Menu
3) Press the Function key for testing the hard drive (usually F2) and let it run.