Lag spikes on some computers but not others

I've been having problems with my internet for a month or two now. The internet drops to the point where LoL or skype or even internet browsing temporarily stop working (but doesnt disconnect) every 2-5 minutes. Other computers on the same network do not suffer the same problem so i'm guessing the problem is with my computer/the connection between my computer and the wireless network.

Any help would be much appreciated

Ben