HP laptop keeps shutting down...

I got a HP Pavilion dv522nr (main specs in sig) used on December 31st. It shutdown randomly one time a week or so ago, and then it did it again a couple of days ago. In the past few hours, it shutdown 3 times. It just completely turns off--like what would happen if one were to unplug a desktop. I got it from my brother, and he never mentioned that he had any problems like this with it.

The cpu temp is generally around 55-60C according to RM Clock. Nothing is shown in the Event Viewer, and it doesn't give any errors when I turn it back on. I tried propping the back of it up an inch or so, and it still did it again. It seems to be completely random, and the only thing I can think of would be overheating; however, the temp doesn't really seem to indicate that...

Does anybody have any suggestions? I looked at a few of the threads I saw as well as Googled it, and most of it seems to be stuff that I've already tried or that doesn't pertain.

mine had a simmilar problem it was a heat issue caused by a dusty hs the temps where about 60-70 but it was enough i guess. also while you are cleaning clean the battery terminals

Take it apart and blow out all the dust. Also update it to the latest BIOS, and apply AS5 to the CPU.

put the laptop on a clear flat surface, download coretemp, and try running prime 95 on both cores. see what your temperatures go up to and see if it shuts down. don't bother opening it. if it doesn't work send it back to manufacture.