|Windows almost always gives a message when something doesn't work. It would be helpful to know what windows is saying about the problem. Just saying they don't work doesn't give us much information.|
But it sounds like what I mentioned above--you just made links to the files and didn't copy the files themselves. It's even possible that since you copied the files to the external perviously that the files are located elsewhere on the external and you're directly copying those links.
Windows likes to hide file extension but if you right click on one of the files that 'don't work' and choose 'properties' it might tell you the extension. If it's a link the extension will be .lnk. It might also just call it a 'shortcut'.
Don't forget to preorder your Hatch green chili for this fall. Many vendors ship world-wide.