Problem with ASUSX53S

Hello all. I hope this is the right place for computer issues.
I recently (few months) have began using a new computer, a cool ASUSX53S notebook, here the specs:
Processor: Intel(R) Core(TM) i5-2410M CPU @ 2.30 GHz 2.30 GHz
RAM: 4 GB
Videocard: GT 520MX (nVidia)
System: Win7 64 bit

The fact is that i am getting random freezes (2-5 seconds then back to normal) during games like CoD4, World in Conflict and also Simcity4. Even Internet Explorer sometimes freezes for a few seconds, but that's rare; CoD4 even crashes sometimes. Now, i know a notebook is not ideal for gaming, but damn this has good specs and these games are not BF3 or Crysys2, so i pretend them to work... The freezing issue seems to be related to the audio, most of freezes take place when there's some audio ingame, like someone saying something or an explosion... I am getting this nearly each minute, stressing me to the limit...
All of the drivers are up to last version, at least the graphic card and audio drivers. I must point out i've RealTek audio drivers which i've heard they're bad.
Last thing, perhaps worthy, is that i tryed to disable both audio drives (screen audio driver and RealTek), then i've noticed that CoD4 wouldn't even start, meanwhile the random freezes would still occur in World in Conflict.

I hope you can help me, i am getting really stressed, my previous notebook was a HP and i thought my computer experience couldn't be worse with Vista, but perhaps i was wrong.

Before this goes in the old topics universe, any help?