Problem with N81Vg, dont know what it is

I recently bought a N81 to play some computer games on and such, but I've ran into this problem and dont know if it's Vista or the computer itself. Counter Strike Source (2004) and Day of Defeat Source (2006) are the two first person shooters I have tried and the problem is this - For like 20 minutes or so, it will run flawlessly with no lag but then all of a sudden without anything changing, every key i hit makes a loud beep and i cant do the action that the key is supposed to perform, and it becomes very skippy/laggy and unplayable. No new programs begin to run when this happens and it's not the connection because it doesn't change from when the game ran fine at the beginning. Could it just be a setting I have to change or is it a problem with overheating or something making me have to return it for a new one?? Thanks for any help.

 

check the temps with HWmonitor when you are playing?

 

Try updating to a newer graphics driver from laptopvideo2go.

 

I had this problem as well;
it could be the IME (input method editor) that popped up and assumed that you're keying in another language.

if you were to try the default left alt + shift, it might switch back to EN(glish) and then the game should be back to normal.