Stuttering when loading web pages (NIS/AV 2010)

I've been using Norton for a long time now without issue, but about 2 weeks ago, I started experiencing the following problem:

 

Regardless of what browser I use, whenever I load a web page, my pc stutters (momentarily freezes).  If I'm playing a video or audio file in the back ground, you can hear the sound stutter as well.   As you can imagine this is extremely frustrating and annoying.   At first I tried the usual updating of my video and sound card drivers, ran a memory check to make certain I didn't have faulty memory.  Ran several CPU and general component tests (using SiSoft Sandra for example),  to make certain I didn't have heat or power issues.

 

I ran virus scans using Norton and Malwarebytes and my system came back clean each time.  I loaded my PC in safe mode with networking and I didn't experience this problem so I knew it had to be software related.  Finally I decided to unistall Norton IS 2010 and the problem went away.  I instaled Norton AV 2010 and purposedly did not run any updates and I was surfing fine.   Once I updated the virus definitions, the problem came back! 

 

It seems clear to me that a recent update caused this problem.  Any ideas?  Here's my setup:

 

Intel Core 2 Duo @ 3 ghz

8 GB Kingston Ram

EVGA Nforce Mobo

Nvidia Geforce 9800 GTX

Windows 7 64bit Ultimate

 

Thanks in advance.