My laptop has a persistent overheating problem even after applying fresh thermal paste to the CPU, GPU, and the southbridge. The thermal paste that I use is Artic Silver 5 but the laptop's temperature is always around 140F during idle and around 160-180F when watching videos then shut down afterward. I've put the copper shims on both gpu and southbride but it doesn't help at all, not even a 1 degree drop. The fan is working fine and I've even try thermal pads too but it didn't help at all. I'm at my whit right now. Please help