Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Self Power

My computer has 2 usb ports, but I needed 4, so I bought the unit. My computer was on when I first plugged it to my usb port. Then I plugged it into the wall, so it would become self powered, and it worked fine for that session. But when I pressed shut down and then tried to turn it on again... The power button was useless, it didn't work. I had to run the unit on non-self powered mode for my computer to run correctly.I don't know if this is my computer's fault, or just the unit.But otherwise it works as advertised.Thanks D-Link