Once again I need help from you guys/gals......

I am facing this problem since morning, my system getting hang for a second or more and then get back to normal again and thats not it its happening at regular interval. I have attached two different snapshots of the situtation illustrating CPU usage, i notice that during that problem my CPU usage shoots to around 80% and then drop back to 2 or around it...... I closed almost all the programs but things remaing same.......

Then i disable my connection for a min or so the problem remains but as soon as i was about to take another snapshot i received a message could not manage to read it completely cause it just vanished in a flash but it was something like unable to execute something.html........

I have scanned my system with adware, Microsoft antispyware, AVG and you can see norton is also running. So any ideas what going on....... Right now i have enabled my Internet connection and running other softwares and things are ok. But soon as i restart the problem also restart.