Boot device not found 3F0

[Kieran2]

Yesterday i was making lunch for kids and i left my laptop on. I cam back and it was doing an automatic repair/diagnostic thing. Then it went straight to a screen that  says Boot device not found, please install an operating system on your hard disk, Hard disk- 3F0.

Its happened a couple times before and ive been able to just restart my computer but now the only other screen i can get to is the BIOS menu. Ive run the diagnostics and it says nothings wrong. Ive tried factory resetting it and there was an error and it couldnt be completed. Ive went through the list of stuff that hp gives on the link on the screen and one of the things i needed to do wasnt even listed in the options. I no longer have a warranty on this computer. I use my computer for school and i dont have the money to get a new one.

[Technicalshamu]

just try reseating ur memory modules and hdd