If Windows does not recognize your external hard drive, please check the following:
In the Control Panel..
Double-click Administrative Tools,
Click Computer Management
Click Disk Management.
-If the drive is external, it is necessary to partition and then format it so that it appears in the workstation.
-See here: New hard drive: what to do?
If the disc does not appear:
-Test with another USB cable
-Try unplugging the drive, turning it off, reconnect, then turn it on
-Install the latest drivers from the motherboard, including the USB drivers!
-Check on the website of the manufacturer of the hard drive if there are no special drivers. Check also if it does not have a section with answers to frequently asked questions (FAQ)
-Check (if possible) the position of the rider in the rack (Sata1/Sata2 for a SATA disk) or the master position (IDE Disk)
-Plug the box's hard drive directly on the motherboard to check if the failure is due to camera or hard drive