Windows kernel Event ID 41 is a very common error to find on out in the Event Viewer, now-a-days on Windows 7 and Windows Server 2008. Microsoft recently published an article about ways to fix those issues.
Symptoms are your computer restarts, and a critical error message is logged in the event log:
Log Name: System
Event ID: 41
Description: The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly.
Why does system Generates Event Viewer ID 41 error ?
The kernel power Event ID: 41 error is generated under different scenarios where the computer is shut down or restarts unexpectedly. When the computer that is running Windows is started, a check is performed to determine whether the computer was cleanly shut down. If the computer was not shut down correctly, a Kernel Power Event 41 message is generated. In the following three scenarios, an Event 41 may be generated
In this post Microsoft has mentioned 3 different scenarios why this happens and how to fix it.
The computer restarted, and there is a Stop error BugcheckCode in the event data
Shut down the computer by pressing and holding the power button
The system randomly restarts and no Stop error BugcheckCode is listed, or the computer is completely unresponsive (hard hang)
Visit: Microsoft KB2028504 for details and fix.