It may just need cleaning dust from the cooling fans.
[link|https://www.youtube.com/watch?v=otPrO7uUel4|Here is a video on how to open the case.]
Remember to disconnect the battery before doing any more work once the case is open.
The laptop is only two years old so it is unlikely the heat paste needs replacing yet, but it may if it is dried out.
[link|https://www.youtube.com/watch?v=1vOOwdHdwYM|Click here for a video on replacing the heat paste.]
Good luck.