Lag spikes on Youtube videos, Online games(Combat Arms), Single player games( COD4) that i never used to have?

On my laptop i used to play Combat arms with almost no lag, my YouTube videos played flawlessly... but lately ive been getting lag spikes that last for about a minute, I thought it was my connection(wireless) so i reset my modem but that didn't do anything and the lag spikes are on games that don't use internet connection. I played Combat arms for about a year with the same LAN connection(so i don't think its a hardware issue) or a public wireless connection, but i guess until i started using my own wireless connection it started to do this. When it lags it the screen with show about two frames for the whole thing and its really hard to pause( videos). Its been happening for a while now its made every game impossible to play... with out cursing in blind fury... I never really played single player games on this laptop but i Dont understand why the same lag happens with this( which makes me think its not the wireless connection). Could this be a software problem? it never used to happen before...