I walked away from Symantec a long time ago. I no longer want any of their software on my computer or those of my clients. It's a long story.
A few months ago, I set up a new X series Thinkpad for a client and one of the first things I did was remove the pre-installed trial version of Norton Antivirus. I thought I was done with Symantec on that machine, but no.
After a couple months, the computer owner experienced a problem with a Symantec DLL that prevented them from running an important application. Yes, a Symantec DLL, specifically S32evnt1.dll, which wasn't even on the computer. It's not clear why Windows was trying to use this DLL (it may be because the application was an old 16-bit one rather than the more normal 32-bit), but the root cause was an incomplete un-install of Norton Antivirus.
In the Windows world, many programs leave files behind after they are un-installed. Symantec had so many such problems they long ago created a Norton Removal Tool which "... uninstalls all Norton 2008/2007/2006/2005/2004/2003 products and Norton 360 from your computer." From now on, after removing Symantec software, I'll always run the Norton Removal Tool, just for good luck.
Fortunately for me, others have experienced problems with file S32evnt1.dll before. Symantec has an item about it on their web site (Error: S32evnt1.dll. An installable Virtual Device Driver failed DLL initialization) which doesn't say anything about how or why the problem occurs, but does have instructions for zapping the registry to fix the problem. They fail, however, to warn you about backing up the registry before modifying it. Still, the instructions, confirmed by a related Microsoft Knowledge Base article, did fix the problem.
A word to the wise.
Update. April 9, 2008: I just ran across this recent Stephen Manes column on his experience with Symantec tech support: When Companies Outsource Support...To Mars! The tech help I got from Symantec: So bad it was downright unearthly.