Question HDD to SSD now games won’t open

[Aaronbmx8]

I recently made the switch from running my OS on a HDD to a SSD. I booted the system from the new drive and went to play a game and it wants me to download them again. But if I go into the hard drive where I save my games I can start most of them that way, how can I go back to launching games from my desktop without having to download them again?

 

[USAFRet]

How did you do this "switch"?
What type games are these? Steam, or other?