Help Please. Windows "Refresh" Tool

Hello everyone. So, I decided, "Hey, my laptop is running slow. Oh yeah, I remember in a past video Logan mentioned that Windows 8/8.1 had a handy refresh tool, which basically re-installed windows for you, without effecting your files. So I thought I'd give it a go. I started the process, of which I would soon realize to be a big mistake. Basically, it did what it said it would do, except it reset all my settings, downgraded me from Windows 8.1 back to Windows 8, and reset my PC's default settings, except one thing was different. There was a folder called Windows.old, which had all of my old files in it. Okay, nothing too peculiar. Except that I had to get my desktop background back from the internet, had to get Google Chrome again,had to re-personalize all my settings, and re-install steam. I thought that it WOULDN'T effect any of my old files, and just re-install windows 8.1? Nope. Now, when I launched Steam, I expected to see all my games sitting there, waiting to be played. At this point I was a little annoyed that I had to go through all of that but then when I logged into my Steam account after going through all that bullshit, I find that Steam recognizes that none of my games are installed. Hm, that's odd, my Hard Drive says they are. I need your help, Tek Syndicate community. How come Steam says this? How can I fix it? Thanks in advance.

 

Edit: Okay so I forgot to mention that my laptop has a 500GB HDD :( but I have about 460GB of Steam games and other programs installed. So I only have 40GB left, when I can't play any of my games. 

Go to install one of them, and tell Steam to install it to the Steam library where all your games are installed, and it should recognize them without needing to reinstall.

@godmode

The correct method to remove your previous windows installation is to press the "super (windows key) + R" and run cleanmgr. Then select "clean up system files" to remove your old install. Or navigate to Control Panel/Administrator Tools/Disk Clean-up - to do the same.

To add/remove system (game) install folders inside of steam, select Steam/Settings/Downloads/Content Libraries (Steam library folders)