The shutdown interruptus

Your old Windows XP computer has been suffering from an intermittent shutdown problem for a long time, but it’s now occurring at least once a day. You’ve also recently started using more graphically intensive applications, and the abrupt shutdown often occurs when these applications are active. Which of these would be the most likely cause of this issue?

Don’t stop believ

Your computer is beginning to experience a new issue where it abruptly shuts down after less than an hour of heavy utilization. You also notice that something is loose and bouncing around inside of the PC’s desktop case when it’s moved. What is the most likely cause of this shutdown problem?