Why my external hard drive not showing up on my computer?
Could be a bad USB port, could be a power cable for your drive that you are missing, could be corrupt windows files, could be how the drive is formatted? (MAC vs Windows idk). Try booting into safe mode, does it detect then? do other computers detect it? Use logic to slowly isolate the cause of the problem. Once you've done everything you possibly can, you can assume your drive is dead and attempt to get an RMA from the manufacturer