What you should do is change the thermal compound of the cpu. Aka the thermal grease. Thermal compound is what helps transfers heat to the heat-sink so that the cpu get's cooled off. Over time the thermal grease begins to dry up, especially if you do things like photo editing/gaming constantly as that puts stress on the CPU. There are videos on youtube that teaches you how to do this, linus tech tips is a great source. However be cautious of how you do it, there are several wrong ways to apply thermal grease.
You'll need
- Coffee filters
- Rubbing alcohol of 70%+
- Thermal paste, I like Tuniq TX-2 as it's not conductive.
- Newegg.com or your local computer part shop (Or other sites if newegg isn't available to you, google around). Walmart won't have this stuff.
- A night of reading up on the correct methods and watching guides.