Unnecessary
My computer has been turning itself off randomly. I have a nice warranty for it. I took it into a warranty service provider and they told me they'd check hardware stuff and before doing any software stuff, which they would need to bill me for, they would call me. They gave me a call saying they couldn't figure it out, so I went in to pick it up. They did software stuff without my consent, and billed me for $25. While only $25, it hurts as I don't have much money to spare right now. Needless to say, I will not go back to them.

You're still under warranty, and yet the warranty people charged you anyway? I smell the scent of something illegal here. Get a lawyer and really make them suffer!
Or maybe something in small claims court would work too? LOL, I don't know WTF I'm talking about...