My 5 year old Dell XPS 1645 is overheating. I was going to just try to replace the thermal paste. However, I'm thinking it might make more sense to replace the fan and heatsink in the same operation. I have a few questions: (1) I'm careful and "competent" but definitely not a hardware expert. Is this replacement something a non-expert can do? (2) If so, am I better off getting the parts from Dell, or is there a third party kit that is better than the original. So far, I haven't found any third party fan-heat sink kits for the XPS 16. Any advice would be much appreciated.