Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Laptops beware

There's a pretty blue light that comes on when I plug this into my PowerBook, but that's as far as it goes. As the tech support site points out the unit is not compatible with the machine -- so why did I have to buy to find that out? They'll happily sell a power booster, but no thanks. I paid for a fully working unit. This isn't it.