Why is my computer showing inaccessible boot device

@treasure25294 that means your computer can't find the boot drive. There are multiple reasons why this can happen. Could be that the BIOS is messed up and the boot order got changed or that you actually have a failed drive. First thing you want to do is to enter the BIOS and check to see if our drive is still being "seen" by the computer. It is in the BIOS where you can also check the boot order. It has to be set to whatever letter your BIOS reports as the drive that has your OS. Most commonly that will be C:

You access your computers BIOS by pressing the "F2" key repeatedly when the Lenovo logo appears during startup.

Use the ThinkPad Edge E320 Hardware Maintenance MAnual To work on your computer. Ultimately, it does sound to me like a failed Hard Drive. You can of course replace it but will lose your files as well as your OS. Hopefully you have a backup of your Hard Drive

Respects to my peers, who are likely correct: make sure that you do not have a USB drive plugged in your computer.