Splashtop, BlackTop and Windows PE are cut down operating systems being used to provide quick access to a few frequently used applications on desktop and laptop computers. The could be a much more energy efficient computers. The idea is that you can quickly browse the web, play a video or check your email without having to wait for the main operating system to boot. On some laptops, such as Dell's, a separate low power processor is used, which greatly increases battery life. If such applications prove popular, then the main computer and operating system could be left unused most of the time.
It may seem bizarre to have a computer with a powerful processor and hard disk left unused, but is much the same as is done with high performance motor vehicles. The four wheel drive mechanisms of most four wheel drive vehicles are not used, as they drive on sealed roads. However, the drivers still value the availability of the system. Similarly some car makers have introduced systems for shutting down cylinders in car engines, so for example an eight cylinder engine operates as a three cylinder engine. It would make far more financial and environmental sense to simply buy a two wheel drive car, with a small engine (my car has a 1 litre three cylinder engine for example). Buying an off road vehicle with a large engine and then drive it on suburban streets makes not practical sense. However, people still buy these vehicles and use them. So it the manufacturers try to make them as efficient as possible. In the same way it may make sense to provide notebook and desktop computers with instant on operating systems and processors, which are what is used most of the time.
It may be feasible to retrofit desktop computers with low power instant on functionality. This would consist of a small nettop PC which was inserted between the peripherals and the main PC. The screen, keyboard, mouse, printer and other devices would be plugged into the nettop and then than would be plugged into the main computer. Most of the time the user would be interacting with the nettop computer and operating system. On those rare occasions when they wanted to do something it was not capable of, the nettop would start up the main computer. In reality this would hardly ever happen. Also, of course, it would make more sense to use a shared central virtual computer, not have one on every desk. But in many cases it is not possible to convince the user, or their ICT staff to give up the desktop PC.
For offices, one workable arrangement might be to build the nettop computer into a VoIP telephone handset. This would then have perhiperals, inlcuding a screen, keyboard and mouse plugged into it. An optional desktop computer could also be connected.