Well it sounds like a heat issue, and certain laptops are more prone than others, it could be one of a couple of things, but being a laptop neither are easy to achieve, so it depends a lot on your comfort at possibly having to open the laptop to gain access if it came to it, but to make a couple of obvious points, I trust you have only been using this on solid surfaces ?
Should you use it on the bed, or floor (carpet), or your lap, you can end up blocking air intake slots, this would choke it's cooling ability, and would suck in dust and similar contaminants that could build up, and eventually cause such heat issues, so always use laptops on a solid\flat surface, even if you just use a hard backed book to sit it on.
But lets keep that on the back burner, it's really only something you'd consider when all else fails, so to start with get and run
Speedfan, keep an eye on temp's for a bit, if they are remaining steady under normal use, play a game, or do something more intensive for a few minutes (gauge this on how long you think before it will crash, then stop well before that point), and report back what the temp's are before and after, probably easiest to post a screen-shot here, it will help see exactly where (if any) heat issue(s) may be.
Next get a can of compressed air, take the laptop outside (or you could blast dust everywhere indoors), but remove any easy access panels before taking it out, possibly 2 on most, for hard drive and ram, but some do have the CPU as well, then using caution (start further away and bring it in closer, up to the point your getting results, without risk of loosening anything that may be close inside), give short bursts until it looks like there is nothing left, then take it back in and close it up, then repeat the above, and see if it's helped at all.
Should there be no change, your possibly looking at reapplying thermal paste to the CPU, this can be a complex job, it just depends how accessible the CPU is, and how comfortable you are doing such a thing, but again this is a last resort, so while we await the results from the above, one thing that can help with heat in laptops is a Cooling Pad, it's simply a "table" for want of a better description, that has x number of fans in it, this varies on the one you get, avoid bargain basement ones, but don't go overboard either, but these serve 2 purposes, 1 they raise the unit in the air by an inch give or take, which gives better airflow under it, and 2 it helps push more air into the unit, all of which helps in cooling the laptop, also keeps you cool if you use it on your lap at all, once we have this info we can try and see what your next move may be.
