So, I heardabout this steam mover thing. I also just got a new HDD, is it possible to be on my SSD's boot and reinstall the games with steam mover on my hdd (which they are already located) to fix the registry? if so how.
No. The OS has to know where the apps are located(in the registry). You have to install the games into the OS.
What steam mover will do is allow you to install to your HDD saving SSD space. Then use Steam mover to create a junction point(and move a game folder) to basically point(trick) the registry to look on the SSD for a game.
If these are steam games, you should be able to install steam, and point it to your games repository, and it should pick them up. If these aren't steam games, you will have to re-install.