Safe to remove m storage device...but I don't even have one plugged in!?

When I start my windows xp pro computer the little icon on the right indicating that there is a m storage device plugged in appears. when I right click it I go through the process of removing a m storage device but I don't have one plugged in!! My computer is running at at least 80% cpu usage due to hardware interrupts from the atapi.sys driver - could this be part of the problem? computer is virus free and adware free. Thanks to all who respond!! appreciate it!