I have a Seagate 4TB external usb hard drive that I believe has fallen (it was attached to a laptop). Now, when I plug it into my laptop, the white light on the drive turns on, but it is not recognized by Windows or Ubuntu. If I try to turn the computer on with the drive plugged in, the computer will freeze on a blank screen before any operating system begins to load. Is this drive repairable? How can I fix it?
What is your goal with repairing? Are you trying to recover the data? Or do you hope to use the drive again?
If you want to recover the data: It depends.
It's very likely that is the data is very valuable you can pay qualified people to repair the drive and access and retrieve the data.
If you want to use the drive again: Don't.
Once a drive has been dropped, if it hasn't already suffered damage to the point of not working, the drive should no longer be trusted for storing anything of any value.