On a Win7 Pro 64bit laptop quad-core that's overheating and crashing due to heat & dust (see http://www.experts-exchange.com/Hardware/Laptops_Notebooks/Q_28415779.html
) the cpu usage is often showing as 100% in the task manager performance tab, in resource monitor, and in process monitor. But when I look at the processes under the process tab of those programs, and sort so the most usage is on top, they read like, 25, 15, 10, 5, then nothing. They don't seem to add to 100%. Why would this be? Does it relate to quad-cores?
Also, this computer can be very slow when RAM, Network, and Disk usage show as very low, and CPU usage shows as 50-80% only. Could this be explained by the overheating?