Hi there BrianTho,
This very much sounds like a dying HDD. So, I would advise you to back up the data that is stored on it as well. On the other hand, it works fine on your friend's computer(which is strange).
If we assume that it runs fine on another computer, you need to check the connections: change/swap data and power cables as well as the SATA ports.
You should also test it with a brand specific testing tool.
Cheers,
D_Know_WD