Hello... Well you can have hardware or software causing this... or just plain over heating too.
1) one place to start would be re-checking all your power connections in your case... make sure all pins and connectors are in their proper place... not pushed out the back or black/discolored.
2) how old is the CPU fan? check that connection... if the MB senses no Fan rotation then that would cause a shutdown... as a "simple test" you can disable/change what the MB Bio's is suppose to do if it detects a fan failure.
3) another option is to read what the OS has recorded for that error at the time of the error.
Here is the Windows event debug screen... and You NEED to be logged on as administrator to the OS...
Right click computer-manage-System Tools-Event Viewer-Windows Logs-System/Applications/Security.... Double Click on the "RED" errors, for more information, General/Details... and files/drivers/Apps, comments/suggestions/information associated with them B )
Expanding Window panes and Posting screen images from here will help Us... But copy and posting text will work too B )
*kernel 41 errors mean the OS was not properly shut down... either by You OR the hardware.