Your computer is not finding the boot drive. Take a look in the BIOS.

Press F10 when the HP Logo screen appears to get into the BIOS menu.

See what hard drive is listed. Select it as your boot device. If one is there and it still does load Windows then either the drive itself is damaged or more likely Windows is corrupted. Does the Windows loading screen come up at all, even for a short time? If it does shut down 2 or 3 time when that screen appears with the power button. Windows 10 will open into the Advanced Start-up environment

While in the Advanced start-up environment, use the following steps to use Start-up Repair:

1. Click the Troubleshoot button.
2. Click the Advanced options button.
3. Click the “Start-up Repair” button.
4. Select your account.
5. Type your account password.
6. Click the Continue button.

If the above doesn’t help do the same as above but this time select “System Restore” from the “Advanced Options?”