GPU question. is it dead? please help

When i turn on the pc the gpu fans go full speed and there's no screen signal. i tried reinstalling drivers and unplugging everything but still doesnt work. any ideas? :( With another gpu the pc works just fine, so the problem is the GPU. but this never happened to me what could the problem be? All this happened while i was reading reddit, all of the sudden i lost screen signal and the gpu fans went crazy. the gpu is only 3 years old.