Hi all, I'm in desperate need of help

Lately error code 12 has made my game unplayable. I was googling for solutions and I found this, which was originally taken from this forum. I followed the instructions to the T and input 'bcdedit /set IncreaseUserVA 3072 ' into my command prompt and restarted my computer. I did this knowing that I have windows 10 and the command might not work for my game. This was a last resort on my part because I was very close to giving up on playing TS3 due to error code 12.

Since restarting my computer, I've been unable to open TS3, Steam, and another game that I downloaded through steam. I click on TS3 icon and nothing happens, I try to open Steam and nothing happens, and so on and so forth. I figured that I would simply undo the command/delete it from my command prompt, but when I open it it doesn't show the line I input earlier. I have no idea how to undo it.

Can anyone help me?

Thank you so much! Yeah, I know I'm a grade A moron, but I was really desperate.