You need to open it up and make sure all of the heatsinks are clean, in a lot of cases, a bunch of grime gets built up on them and it can't get rid of the head as efficiently. Also, make sure you aren't blocking any of the vents during usage of the laptop..
After all of that is checked, you need to make sure you're not loaded down with trojans or other various viruses to make sure they aren't using excess CPU power. If you're overclocking in any manner, that could be the root of your problems, because that'll cause the CPU to be more hot than usual.
Also, you need to keep in mind that laptops are generally warmer than desktops, due to all of the parts being in such a compact place and what not.. The ambient temperature in the room you're using the laptop could effect the computer's temps as well, so if you're in a hot, humid room, that could be your issue.
List all of your recent hardware changes, and the programs that you normally have running. If you have an AV installed, I suggest closing it out during gaming and what not, because that'll eat up processing power. It's more than likely crashing due to the high temperatures, as a type of failsafe to avoid damage to the hardware. There's been a few times where my rig got too hot when I didn't tighten down the heatsink and fan on my CPU by accident (I was drinking, felt like changing the thermal paste, so yeah..) it overheated a few minutes after Windows booted up and shut down to avoid damage to the hardware.
I seen a GPU a few weeks ago, a GTX 260, with a completely clogged heatsink.. The person complained of it overheating and what not, and I just had to facepalm, lol.. Cleaned it out, replaced the thermal paste, and the thermal pads for the RAM chips, and it was running cooler than it ever had been.
Also, make sure you didn't bend or damage anything on the heatsink, because that can result in crappy efficiency when it comes to pulling heat off of the CPU/GPU.. Don't listen to the person telling you to defrag, because that isn't going to help your CPU issues.. I'd suggest backing up the files that you can't replace on the laptop, and doing a clean install of Windows 7 Ultimate 64bit (32 if you have less than 4 GB of RAM) If you do that, then you can rule out and malicious software being the root of the problem.
Where is your HDD located within the laptop? Is it mounted anywhere near the CPU? Check the temperatures on that and let us know, the HDD could be faulty and could be putting off a lot more heat than normal.
If you've heard of people having issues with the same exact laptop you have, it could just be a design flaw.. How long have you had it? Were these issues present when you first bought it, or did they gradually start to happen? I'm willing to bet a design flaw within the casing of the laptop compromised the ability to keep itself cool.. It could be anything from the usage of crappy heat-sinks that were too small for the components, weak fans, or even just horrible airflow.
Also, it's kind of difficult to bend anything on a heatsink just by spraying it down with a can of compressed air.. I'm sure it's possible, but it'd have to be a strong airflow to bend the metal.. I've only damaged a few heatsinks in my time, and they were the crappy ones from the older revisions of the Xbox 360, such as Xenon (I did it on purpose, I wanted to see what would happen when I slammed the pieces of crap on concrete
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