I installed NORTON 360 version 2 (All in one security)on the...

I installed NORTON 360 version 2 (All in one security)on the weekend, and now I'm finding that my whole system is slower than before I installed the package. Could that be due to my RAM and that I need to put more RAM on my computer??
The refreshing and accessing pages are a bit slower than before the installation..........

Thanks for any suggestions...........