the power event id 41 is logged when the machine boots after a non graceful shutdown.
IE a bugcheck, or loss of power, when you reboot the machine the system will detect that shutdown never completed and it will run some extra checking and log this error.
a machine check exception is generally called by the hardware, if the first parameter is 0 it is called by the CPU. if it is 4 then it is called by something attached to the CPU like the PCI/e bus. (depends on the generation of the machine)
generally, overheating, overclocking in bios, overclocking the CPU or GPU, under powered power supplies are the type of things you would be looking to fix.
on older machines, sometimes you can just blow out the dust and get the fans working faster to prevent overheating.
it can also be the power supply not producing proper power. I have even seen cheap power strips be isolated to this bugchecks.
main point is the power 41 entry is not the cause of the problem, it happens on the next boot after you have a problem.
you may want to look in c:\windows\minidump directory and see if you have any memory dumps recorded. The dump will indicate why windows shut down the system.