I observed this on my HP Laptop dv8t 1100: Sometimes I inadvertently had unplugged the power cord to the laptop. For some unknown reasons, if the power cord is unplugged (battery not being charged) suddenly the CPU usage would go up to the roof eventhough the computer is not really doing anything. Latest instance: I noticed the laptop slow-down - only a few webpages were opened and nothing else... nothing out of the ordinary. The laptop felt as if it was freezing up. I checked the Task Manager, Performance tab: the overall CPU usage ws 65%! All 4 cores and all 4 hyperthreads were at 60-70% use (never seen it like this even during the busiest trading moment). Once I realized that the power cord fell off and re-plugged that in... voila... usage back down to about 14% instantly. The screenshot was captured moments after I plugged back in the power cord. You can clearly see the difference. It seems as if the laptop is fighting for something, or in a thrashing mode when the power is unplugged. I can't figure out what it is. These laptops are designed to work with or without the power plugged in for a few hours. As it is I can't use this laptop when I travel. Appreciate it if anybody can offer some possible explanations what caused it.