Post originale di: chaz ,
Hello If you can reset the SMC + PRAM ok and have never spilled liquid on your machine. I’d say your problem is the thermal paste on your cpu / gpu is dry, has dried out, as its an old machine. And needs replacing quick i.e a good service is needed. Clean out the rear fan grills also of fluff and hairs etc. Your machine is shutting down because it is hot. Shutting down is a safety feature.