Lag Moments When Working/gaming

i have been pissed off by something that almost every 60 seconds, my computer goes really slow, internet browser is hard to open, my games lag like hell, and stuff like that. And I have searched for help from all the internet, but all of them are saying that i should reboot my WLAN or something. The thing is, that it's not the wireless that is lagging, it's not my internet, it's the computer.

I have an awesome laptop that runs nearly every game perfectly, but every 60 secs, my laptop lags like hell and it's annoying to play. And even when i am playing singleplayer, it still lags. In internet games it's so disturbing because i cant pause the game for 60 seconds cause of the lag. So I really would like to hear some help because this is lame.