Randomly Inserted Javascript Code

I use Phil Ringnalda's archive script generator to display a dropdown menu at the top of my blog's navigation bar so readers can jump to an archive page for a particular month. It works great... except for on my home computer.

For the longest time, I could not figure out the problem. At first, I thought I had turned off javascript in my browser... Nope. Then I thought it may be the combo of my browser and operating system. That wasn't it either. I finally selected "View Source" on my browser, and saw unfamiliar code:

<script>
<!--
function SymError()
{
  return true;
}

window.onerror = SymError;
var SymRealWinOpen = window.open;
function SymWinOpen(url, name, attributes)
{
  return (new Object());
}

window.open = SymWinOpen;
//-->
</script>

Further down, I saw some more:

<script language="JavaScript">
<!--
window.open = SymRealWinOpen;
//-->
</script>

Where the heck did this come from? I searched my Blogger templates and archive page to make sure that I hadn't inadvertently added these unwanted lines but they didn't show up there. I did a Google search on these unwated function names, and found a well written page explaining that the culprit is Norton Internet Security (NIS). Unfortunately, the only way to disable this "feature" is to uninstall NIS from my home computer which is less than ideal since there are many features of NIS that I think are helpful. More worrisome is that other visitors (okay, all 3 of them) who come to my site may experience the same thing but won't know that something is wrong. What a pain. Another reason to switch to Movable Type?