Stuck on "waiting for device" while rooting

[AC Question]

I tried rooting my samsung galaxy s5. It got stuck on 99% and nothing would happen for over 3 hour. The downloading process already started on my phone and the Kingo app on my computer said "waiting for device". It seemed like my computer wasn't reading my phone even though it was plugged in. I unplugged the phone but now the Kingo app restarted and it doesn't "see" that my phone is plugged in. I basically cannot turn my phone off or I'll risk hard bricking it, but I do not know what else I can do to fix the situation. I am in no way an expert in this and I absolutely need some help.