It is quite common for computer users to experience spikes in CPU usage. Usually it is due to the genuine load of computer applications on the computer resources and the reason is legitimate. On the other hand, if you notice a constant high usage of CPU, it means that there is some problem with your computer.
You can easily track CPU usage by accessing Windows Task Manager. This tool can be viewed by pressing Ctrl, Alt, Delete simultaneously. It also has a Performance tab where you can monitor CPU usage history. In case the history graphs show a trend of high usage then you need to rectify this problem.
Here are some of the common issues that are known to cause high CPU consumption:
Several types of malware including virus, trojans and spyware are known to attack the CPU resources of your system. By far, malware is the single largest reason behind high CPU consumption. They create havoc on your system by launching destructive or useless processes that hog CPU resources and render your system virtually inoperable.