How to shutdown constant guard which is slowing my system

I purchased this new Sony Vaio laptop. I am running a Windows 7 Operating System and my system specification is quite good enough to run my system fast. However, I downloaded this Norton Anti Virus and Constant guard as these are being offered b y Comcast. Since then, I notice that my system is running slow and applications started to crash.
So I uninstalled Norton Antivirus as this maybe causing the issue. I still experience crashing issues after uninstalling Norton. Therefore I conclude that it’s the Constant Guard that is causing the issue. I don’t know how to turn this off. Can you please provide instruction on how to shutdown constant guard?
Appreciate your help on this matter.
