Today i tried instaling version 1.12.2 to play a server with my friend on pc edition, but it said that it could not downlaod realms 1.8.9 jar. I tried uninstalling minecraft and now its with every version, i cant play minecraft now, how to fix?

also all my files are gone and i think thats why it fails, how do i get them back?
Failed to download file. patchy-1.1.jar
Name: patchy-1.1.jar
URL: https://libraries.minecraft.net/com/mojang/patchy/1.1/patchy-1.1.jar
Error details: UNKNOWN/-138
Filename on disk: patchy-1.1.jar
Path: C:/Users\Legen\AppData\Roaming\.minecraft\libraries\com/mojang/patchy/1.1/patchy-1.1.jar
Exists: false