We have a Server 2003 quad core processor HP box that is running as a file server. It is not running any applications. Even the Trend Microware anti-virus is turned off on this machine.Sometimes once a day and sometimes once every few days the CPU's will go up to almost 100% usage and stay there. Users cannot access the server while this is going on. After ten to twenty minutes the CPU will come back down on its own to normal CPU levels. When this is happening Windows Task Manager shows that the SYSTEM process is using all of the CPU. I am going to put Process Explorer on this machine so that I can see more information on the SYSTEM processes. Can someone help me troubleshoot this further so that I can eventually find a solution? Is there something more that I can do to track down the problem?