I have a 5155 and it is getting pretty warm at times.  The warmth is coming from the center back of the bottom. The plastic gets pretty warm. When I plug the charge cable in the temp spikes into the 90c range before the fan brings it down.  I was thinking of replacing the thermal paste to see if that helps or would that void the warranty? Or is there a way to bump the fan curve up?  I would like the underside of this laptop to not get so hot so I can actually set it on my lap once in a while without it feeling like I was going to get roasted. 

Thanks.