Issues with Norton Antivirus 2010

 Hello, I'm Bridget and I was wondering if I could get some help with Norton. I know only pretty basic things about computers, so please bare with me. 

 

 

Ever since I installed Norton I've noticed 1 thing, and that is that my computer lags now. It fact, it lags a lot. 

It took me about 30 minutes to open a new folder, rename it, and put about 3 small pictures in it. 

 

Also, I think Norton has been automatically deleting my cookies, I can't stay logged on to most websites for more than 2 minutes tops.

 

How do I stop this from happening? What can I do?

 

Thanks in advance, and Merry Christmas. ^^