When was the last time you physically cleaned your computer? The two biggest culprits for overheating are insulation (the computer not being able to breath thanks to dust) and the thermal compound going bad..
I'd try the first the one as the easiest fix - get the canned air and target the video card and cpu fans through the case
If that doesn't work, most likely the thermal compound/paste needs to be reapplied to the video card (this is the paste the transfers the heat to the fan to blow it out..when this goes bad, your laptop can keep over heating.) I had to do this on my gaming laptop not too long ago, which was about as old as your computer. thermal compound is cheap (under $10). however getting to your video card is the fun part
Do you know what temperatures you're hitting? 75 degrees celsius should be your limit - when you get into the 80ish range you could start theoretically start damaging parts, and if you get into the 90s or even 100 its possible to completely burn the card out.