DaemonUmbra

Did you delete the folder like I said or did you just delete everything in it?

Delete the libraries folder and run the launcher NOT as admin, then try installing Forge again

I asked you a yes/no question and you replied with "it's still not working"

"What were you doing when the pain occurred?" "It hurts, doc!"

Did you run it as admin after you deleted the libraries folder?

Can you provide a screenshot?

I get the feeling you are talking about the Forge installer rather than your Minecraft Launcher that I asked about

Do you run your Minecraft launcher as admin or something? (Note: I'm not saying "Do so" I'm asking if you already do)

Yes, you might want to check JEI's settings (click the spanner/wrench) to see its search operators

If you run it from the command line, what shows up?

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

Really old Minecraft versions are no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

Please provide your debug.log as described in the EAQ and the logs section of my signature below

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

Try this: gradlew build --refresh-dependencies --rerun-tasks

1.7 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

Have you tested without Optifine installed?

Please refer to Optifine's changelog regarding Forge compatibility

1.8 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

1.12 is no longer supported on this forum. Please update to a modern version of Minecraft to receive support.

Please provide debug.log as described in the EAQ and the logs section of my signature below

Try without Optifine and OptiForge