Welcome to the community, Laquicia!
I'd advise you to check how the external HDD appears in
Disk Management as well. If you are able to get the drive detected there, make sure that the file system is NTFS or FAT32/exFAT and that the status is healthy. While there, you should try right-clicking on its volume and see if you'd be able to
change the drive letter & paths. This might help you get access to it from This PC/My Computer.
As soon as you do that, make sure you backup all the data from it elsewhere and have one more copy of your files. This is the best way to prevent any potential data loss.
Did your stepdad initialize the hard drive after you had stored any files on it? Did you/he transfer any new data onto it after the re-initializing on the TV?
Keep me posted.
SuperSoph_WD