How to troubleshoot power-supply issues?

Question

I have a PC running Windows 7 that sometimes reboots randomly. The Event View-er shows the following

Date: 6/26/2016 5:13:51 PM

Event ID: 41

Task Category: (63)

Level: Critical

Keywords: (2)

User: SYSTEM

Computer: ComputerName

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.

Event Xml:

<Provider Name="Microsoft-Windows-Kernel-Power" Guid="{331C3B3A-2005-44C2-AC5E-77220C37D6B4}" />

<EventID>41</EventID>

<Version>2</Version>

<Level>1</Level>

<Task>63</Task>

<Opcode>0</Opcode>

<Keywords>0x8000000000000002</Keywords>

<TimeCreated SystemTime="2016-06-26T14:13:51.192411800Z" />

<EventRecordID>342359</EventRecordID>

<Correlation />

<Execution ProcessID="4" ThreadID="8" />

<Channel>System</Channel>

<Computer>ComputerName</Computer>

<Security UserID="S-1-5-18" />

<Data Name="BugcheckCode">0</Data>

<Data Name="BugcheckParameter1">0x0</Data>

<Data Name="BugcheckParameter2">0x0</Data>

<Data Name="BugcheckParameter3">0x0</Data>

<Data Name="BugcheckParameter4">0x0</Data>

<Data Name="SleepInProgress">false</Data>

<Data Name="PowerButtonTimestamp">131114239970732138</Data>

I am in the process of ruling out the software problems, but I don't know how to troubleshoot power-supply issues.

Answer 1

Microsoft has provided a KB article about your sporadic reboots:

Windows Kernel event ID 41 error "The system has rebooted without cleanly shutting down first"
https://support.microsoft.com/en-us/kb/2028504

Your important part is Scenario 3:

The system randomly restarts and no Stop error BugcheckCode is listed, or the computer is completely unresponsive (hard hang)

To check whether this scenario is occurring, press the CAPS LOCK key on the keyboard. When you do this, if the CAPS LOCK light on the keyboard does not change when you press the CAPS LOCK key, the computer may be completely unresponsive (hard hang).

This scenario usually indicates a problem with the hardware. To help isolate the problem, check the following items:

1. Overclocking: Disable overclocking to see whether the issue occurs when the system is run at the correct speed.
2. Check the memory: Verify the memory by using a memory checker. Verify that each memory chip is the same speed and that it is configured correctly in the system.
3. Power supply: Make sure that the power supply has enough wattage to appropriately handle the installed devices. If you added memory, installed a newer processor, installed additional drives, or added external devices, such devices can require more energy than the current power supply can provide consistently.
4. Overheating: Check whether the system is overheating by examining the internal temperature of the hardware.
5. Defaults: Reset the system back to the system defaults to see whether the issues occur when the system is running in its default configuration.

Checks those steps to detect hardware issues.