Are my suspicions right here? *laptop heating problem*

Sounds like overheating. Cleaning the dust out and applying new thermal paste will help, but doesn't necessarily mean it will stop the problem.

i don't know i have an acer with a pentiu t4400 but with hd 5650 1gb 2 gb total and it run very good and even managed to play far cry 3 on it on lowest settings but it always heats like hell, even burned the chargers head on my pc

try to clean the fan and/or buy an external fan or as you said change the thermal paste but i'm not sure if it would help alot

thats why i am finally happy that i have a decent pc now

you need to clean the fan. I would advise seeking a professional to do it

I had same problem I couldn't play any damn game on my laptop even indie games lagged as hell, cleaning fan and changing the thermal paste helped after that I was able to play Far Cry 3 on high setting no lag.

You should check your heats with SpeedFan or any other temp monitoring program.
If it's a heating problem cleaning dust will propably help a bit.

You should pee on the laptop when is too hot.. I tried and it really works..

Try dusting it with compressed air (you can buy those in any PC shop). Also thumbs up for having the patience to play on that thing, I do have similar laptop for my school work and everytime I am forced to play on it instead of my desktop (weekend at my parent's place etc.) I just feel miserable. Good thing there are plenty of oldies and indie games that it can run, but I just cannot imagine playing something more recent than 2002 on it.

I had the same issue - 8~ years ago.

It's definitely overheating. Buy compressed air and remove the dust.

Yeah, it's probably a heat issue. They are super common amongst laptops, because space is a serious issue, and seriously impedes airflow, thus making laptops get much hotter than a desktop. However, your issue could have nothing to do with merely thermal paste. All that does is provide thermal conductivity with the heatsink.
Also, you're assuming it's the CPU overheating and not the GPU, which is even more likely where gaming is concerned.

As others have said, cleaning the thing out is a definite step one. However, please note that laptops are a clusterfuck of small parts smashed into a small space. They are a pain in the ass to disassemble, and you have to do that even just to properly clean one. If you don't have some fair experience with computer work, I would generally highly advise you not try to do any of this stuff on your own, since there's a pretty significant chance that you will end up trashing your laptop. If it wasn't your primary means of computing, I'd just say "F-it, go ahead!" However, since it's your "everyday" and what you use for gaming, I'd suggest some real caution here.

have same problem here with Acer Aspire 5560G turn off automatically after 5-10 mins of playing Sniper elite v2, Just cause 2, Red orchestra 2 on lowest graphics but plays Borderlands 2, cs go, Mafia 2, L.A. Noire on high graphics with no problem

Thanks a lot for the help guys!

Last summer got the same problem on my Acer Aspire 5750G(2years old at that time) and had the same problem with my laptop reach 105°C in 2-3mins after launching BL2/GW2 . My fan was broke so had to change it,so you may see if your fan is working somehow(was easy for me to see it,just removing laptop's keyboard to see does it work). But yeah,you may end up changing cooling system because acer's is often crap.

'What about the thermal paste?'

Don't expect to much from thermal paste. If you have been able to remove/exclude the potential dust problem and still have issues with high temperature, watch out for a good Notebook Cooling Pad. They can do wonders to compensate weak cooling systems.

I have a Deepcool N8 with two powerful 14cm fans and it works great ...and looks great too, with its thick aluminium plate!