While i press a key under a game like half-life or other, my mouse does not answer. And the keyboard sometimes forget to unpress my key when i pressed one for a long time. And i noticed it was also hapening under the Os in itself. I can't help fixing it alone so i need your help.

The keyboard problem may be related to a faulty key,keyboard matrix or even just crumbs under the keys[to many biscuits with your coffee ;)].Try another keyboard to see if it disappears. The mouse problem could also be wear on the key actuators it all depends on what type it is,as before try another to see if it cures the problem.

I have exactly the same problem, I've tried a different keyboard but the same thing happens.