Ugh, Norton. That's one of the worst pieces of software I've ever encountered, at least in the domain of "serious" software.
Your using norton...? Godspeed.
If every release of a piece of software has not only not done its job well, but lead to system instability and avoided being properly removed when using the bundled uninstaller, I tend to be skeptical of any newer releases. It is very rare that the quality of software changes so radically, and that usually only results from a complete change in management.
True, my Norton Internet Security 2004 became corrupted on its own and caused some troubles on my old computer such as system instability; some component of NIS 2004 would often encounter an error and be terminated, causing my explorer.exe to have to reload. NIS 2004 also lagged my computer many many many times because it seems to adore scanning thumbs.db, which was freaking annoying.
BUT it did block out unwanted porn ads on some bittorrent-search sites, and that was in 2008 about 3 years after my Live-Updates license expired and 3 years after I haven't had a single Live-Update date.
How did I know that Norton was the one blocking those porn ads? The moment I uninstalled Norton Internet Security 2004, the porn ads appeared on those sites to my surprise because I had been using those sites for a year or so and hadn't seen them before.
And I tried numerous other Anti-adware programs and Anti-virus (with anti-adware bundled with them) in an attempt to solve the porn-ad program, but none of them worked.
That is the reason why I believe Norton Internet Security is one of the best there is out there.
With Norton Internet Security 2009 onwards (I just bought and installed Norton Internet Security 2010; no problems so far) boasting of a fast & lightweight Smart Interface and NIS 2010 coming bundled with anti-adware, I think Norton has just reinforced its position in my choice of Firewall & Anti-Virus & Anti-Adware products.