Experiences with dell and HP products in the past has taught me that they like to go one of two ways. They either apply a TON of thermal paste to all the heatsunk chips, OR they apply a tiny amount of really low quality stuff.
While it's apart, re-mount the CPU/APU cooler using a proper amount of decent thermal paste
Oh, and this time of year, I find that ambient temperature starts becoming a problem, for me at least.
What temps are you actually seeing? 80-85C is pretty normal for a laptop with a decent CPU, especially an AMD CPU as they have significantly higher TDPs.