Which model is the Alienware? I am assuming it is a desktop since it is liquid cooled. What is your CPU? Is it overclocked?
I doubt that a game could have caused this. It is possible that a virus could be opening several processes at once, but task manager would show the load to be much higher than 10%. Based on the info you have given us, I still believe that there is something physically wrong with your hardware. Even if your pump is working, there is a possibility that the system has developed air pockets. Just like in a car's cooling system, a PC's liquid cooler cannot have any bubbles or air pockets in it. The system needs to be purged or bled of any air. If the system is closed loop, it is impossible to do without destroying it. If there is a reservoir on the system, then it most likely can be purged.