Laggy

Heyy recently my computer has been running REALLLLLL SLOWWWW. and it shouldn't be the laptops problem cause it's quite new (less than a year old). I use Norton Internet Security and the scan shows nothing that may be affecting this. Are there any other reasons? (it takes 5 to 10 seconds for a click of a mouse to respond and it's frustrating) And another thing. my CPU usage shows something that ranges from 56% to 98% when i'm not running anything or when i just have Google chrome open. That is pretty scary...