@gmej1your computere can either not find / read the hard drive (HDD failure)or the files on the hard drive are corrupted (OS failure)
You need to try and access the BIOS on the computer and see if the BIOS can see your hard drive. If it does not it is most likely a failed hard drive. To repair that you would have to replace the drive. The "owners manual" downloadable [http://www.dell.com/support/home/us/en/04/product-support/product/inspiron-14-7437/manuals|from here] will tell you how to work on your hardware.
To access your computers BIOS try this:
Turn on your computer.
Press "F2" during boot when the "DELL" logo appears.
Press "Fn"+"F1" after the computer has powered on if "F2" does not work. The BIOS menu will display with a list of options.
[https://www.youtube.com/watch?v=wXPqoOqJPh0|This video]should be pretty identical to your BIOS as well. It is within the BIOS settings that you can set boot mode to USB drive and try to boot from your flashdrive. It has to be bootable. You could also use a Live CD version of Puppy Linux and use that to boot. With that, try to access your hard drive.