Your argumentation isn't logically sound because you're missing one very important part: it "goes black" for YOU. If you died now absolutely nothing would stop for me, so your basic assumption that everything stops is already wrong.

If your argumentation was true, then this would also be true for any device with any form of sensory input.

A laptop being shut down and never turned on again also makes "everything go black" from the perspective of the laptop itself. Does that now mean that the laptop in question was the only true being in the universe? Obviously it doesn't.

And you as a human aren't special in any way shape or form either. Your singular experience ceases to exist, nothing less, nothing more. Same goes for any experiencing being that ever existed.

Everything "went black" for every single person that came and went before you.

Also it doesn't really go black. It goes nothing. Your experience is gone, thus you couldn't experience black either. Everything, including the perception of time, stops for you, thus nothing ever can happen - from your no longer existing perspective.

Now to make it interesting again: Your basic idea of being the only true being may still be true.

Scientifically speaking there is no way to prove or disprove that you aren't hallucinating everything, including me. Even if I lay out the perfect reasoning of why I exist to you, you could've just as well imagined it. From my perspective this obviously means that I may very well just explain to a hallucination of mine how I could be a hallucination of it.

This goes for every single statement that is outside of science though. God may exist, you may be a Boltzmann Brain imagining reality, this may be a simulation, this may be a single version of a multiverse like a decision tree - all these "fun to imagine" scenarios are outside the realm of science. Thus they may very well be true (or false), but we will never know.

Which is also why science never states absolute certainty and only models what agrees with observation.