I was using the laptop then all of a sudden I get the blue screen of death. When I tried to restart the PC, it said boot device not found – install operating system on your computer. How can I fix this? Have I lost Windows 10 from my laptop?
Sounds like the hard drive has died. Check in the BIOS to see if you can see it listed there. If not, the hard drive is no longer being detected by the computer. (And the hard drive is where your bootable Operating System [such as Windows] resides).