you can bring up task manager and see which proccess is it that cause
the 100% cpu usage.
terminate that procces and see what happens.
if the procces is called (system idle procces) it is not right the cpu usage
it is a fake report.
you can check your cpu,memory use by using freemeter.http://www.tiler.com/freemeter/
if you find it try unistalling the aplicattion that uses it.