Kernel Power Critical Error, event id 41

Your last sentence caused me to realise none of your recent unexpected restarts have resulted in the production of a dump file.

Most system failures result in a BSOD (Blue Screen of Death) and a dumpfile report is created providing that the computer has been configured to create reports.  In a limited number of system failures no dumpfile is created. A report is generated when the computer is next booted and placed in the System Log in Event Viewer. The report is given an Event ID number 6008 and gives very little helpful information, save that the cause is unknown and that it occurred at the date and time specified. . A further report is placed in the Reliability Monitor with a red orb on the Miscellaneous Failures line and it is recorded as a Critical Failure. Unfortunately the Technical Details for this type of failure reveal no additional information.

The more common causes of this type of failure all relate to power failure.

These can be because:

1. The user has pressed the Power On / Off button.
2. A power failure or a loss of supply to home or office where the computer is located. If this has happened it will often be obvious because electric lights are other electrical appliances switch off.
3. A faulty electrical appliance on the same electrical circuit as the computer or the computer trips the contact breaker or blows a fuse and switches off the supply for safety reasons.
4. The power cable between the mains power socket and the computer becomes disconnected at either end.
5. A power surge or lightning strike occurs. Your computer should connect to an uninterruptible power supply unit, which then connects to the mains supply. If an incident occurs you will have to reset the uninterruptible power supply unit. Without one of these units in place a lightning strike or power surge can damage the computer beyond repair.
6. A faulty power supply unit. The best test here is to remove the existing power supply unit and replace with a known good power supply unit having the same capacity. Most home users do not keep a spare power supply unit to hand.
7. A damaged or disconnected power cable or motherboard connector within the computer. You can check the cable is properly connected but a damaged motherboard is not easily checked.
8. If the computer is a laptop check whether the battery can be fully charged, holds the charge and was or was not connected to a mains supply when the failure occurred.

A related Microsoft Knowledge Base Article:

http://support.microsoft.com/kb/2028504