I have two WORKING laptop Hard drives EXTERNAL both used for backup in USB cases.

I wanted to install one on my Tyros......so before I did that I DELETED all the files on the Hard Drives on my PC....

Now they dont work in the Tyros....They will not be recognized in my PC USB ports either....is it possible that I deleted some kind of utility files that make these things work....if so how can I fix them or reinstall the files....I cannot format them either they wont show up on the PC.....HELP?