While overheating is a real possibility, you should check for it first before jumping to conclusions.
To check your temperatures, download and run HWMonitor from here:
http://www.cpuid.com/softwares/hwmonitor.html. This will state the temperature of different components in the computer. Once that's open you should start the game and run it for a while (But not long enough so that the machine completely freezes). Afterwards, close the game and see what temperatures it shows under "Max" for both your CPU and graphics.
Post these temperatures here along with the specs of your machine, that will help determine if overheating is the cause of the problem.
