External Hard drive isn't recognized in diskmgmt

[ksterritt88]

My external hard drive isn't recognized by 'my computer' or 'diskmgmt'. It will pop up in 'devmgmt' and it illuminates when plugged in. It also makes the Windows connection noise.
I'm a teacher and have many important files on this device.
Any way to recover?

 

[MaikuTech]

Before we even get into that lets start with some information about both of your computers.
Name of external hard drive, total space size in the hdd.
Connection type, usb 2.0, usb 3.0, firewire:
Names of the OS on both computers:
System specs of your computer at home, minimum specs of your computer at school ?
Is your cable connected to the drive working with anything else ?
If the cord is bent or has the slightest cut on it it will make things hard for windows to pick up on,
The reason why I am doing it this way so I know what I'm working with.