Lag issues

I haven't had this issue before. It just started about a few months ago when I've had this issue. It runs everything completely fine for a decent amount of time. Such as(RaiderZ, League of Legends, Smite, SWTOR, Minecraft, OSU). Even when I'm browsing stuff like Facebook, Memecenter, youtube. It runs it completely smoothly then it just framerates out on the games. For when browsing the page just freezes. It doesn't stay like this forever. It eventually goes back to normal, then it goes back to its lagging state, and this happens over and over again. Though I never had this issue before, I am not sure what I did. I even reinstalled the OS. Can someone please help. I would like to go back to my games without this issue of running smoothly then lagging out to the point where I can even play. System Specs Processor: AMD Athlon II Dual-Core M300 2.00 GHZ Video Card: ATI Mobility Radeon HD 4200 Series(Believe it has 256mb installed memory) RAM 4GB, though it says 2.87gb Useable(Whats with that?) OS: Windows 8 I do have a monitor, keyboard and other stuff attached to my laptop. If that is causing lag issues I'd like to know. Someone please help me with this issue. Thanks~

I also you Advanced System Care(Beta 2.0), Smart Defrag, and their Malware Removel(Antivirus program) from iobit.