Is my HD 7870 dying?

I am using an AMD Radeon HD 7870 graphics card and from last couple of days when I am playing any games, my computer will shut down on its own. Yesterday I decided to take out the video card and it was surely very dusty. So, I cleaned off all the dust and then reconnected it again on the PCIe x16 slot and also installed the latest driver from the amd website. But after testing some games my pc is again shutting down automatically. So does this mean that my GPU is dying? Any ideas

Can you please tell us about the whole computer specifications that you are having? It seems to be that either the Power Supply must have gone bad or else there might be CPU overheating issue. Since you have cleaned the graphics card then there should not be an overheating problem with the GPU. Can you try to clean your CPU heatsink and also take it off and reapply thermal paste over it. After that test any games on your pc and see the difference.

Even I am thinking that your CPU might be overheating, so download a tool called HWMonitor to check what temperature reading you are getting. After installing HWMonitor, the application launches and displays the information about the voltage of your PC, temperature, etc. A menu gives you access to the tool including "Help" which is only accessible for holders of the paid version. Finally, HWMonitor shows all the necessary information and alerts you if your computer is running on a temperature too low or too high.

Can you try to run Prime95 stress test which will only stress the CPU. If the computer shuts down then it might be a power supply issue. Prime95 is a small community design software whose purpose is to find the largest cpu stress, pushing the computer processor to the maximum. Its principle is to calculate highly complex computer operations and pushing to their maximum CPU, RAM and motherboard. If this produces no error: the system is stable.