Please school me on external video adapters that plug into a USB2 port. What exactly they can and cannot do? I understand that full-screen video would be out of question, but are they fast enough for things like editing Office documents, reading PDF files, using Remote Desktop? Or are they strictly for static pictures like Powerpoint presentations? I want to be able to use an external monitor with my pocket size PC. It does not have any video outputs, so a USB video adapter is my only option.