I just built a new computer. All my games are installed on my seagate backup, but they wont launch from there. I can't launch the uninstall / install / repair either. Any suggestions? I hate to have to delete the files individually, re download the game then reinstall.

Easiest method would be to install galaxy, tell it to scan the folder where the games are installed, and let it finalize the installations. Reason they are not running is because they are missing dependencies, be them redistributables, registry entries or other installation information. So you would need to install them again, but Galaxy may be a bit faster.

P.S. Not all games keep their saves in the installation folder, so you may be missing your saves as well.

migrate to Linux and forget what is "registry" with all its problems. :)

Why do you have your games "installed" on your backup drive? Store the installers on a "backup" drive and install games on your machine. Otherwise its not a backup drive at all, backup means store you only go back for recovery, not day to day working. Also note the installers should be less space than installed copy, so you can store more.

This is not a backup then. I have multiple ssds with various OS's on, and data drives in the machine - this is the working system. I then have a raid box for daily backup, ie a separate hdd for backup where i store my failsafe - this being the ability to go back and restore any from original files. I then have a longer term back up system off site. The backup part has nothing "installed" on though. The reason is I want a minimal storage with no ties to anything else. Installation means that various files are installed, dependencies such dx, cpp, links in registry, folders in system areas not to mention that things maybe installed in different ways on different setups, etc. Now if you swap out drives none of that will be present, hence why you have problems. If its just a matter of saves, almost all games just store these as files, you can copy these across installs - for a lot of games I also backup these saves, so I only needs to install, plonk the saves in and away we go.