Interesting post.
Don't know what to make of the hard drive errors you had back in the day. I've seen it happen where this error cropped up on restart after a clean install of Windows using imaged software (as IT folks are wont to do) - the result often due to missing or corrupted device drivers (namely the IDE controller) on the imaged copy. Normally not a problem if the OS and device drivers are up to date before adding application and/or security software on top of it from what I've seen. Too far back and too many variables to say for sure, but I think the OS would be the more likely culprit.
Other comments keyed to the succeeding paragraph:
1. There's a spate of automatic set-and-forget features with NIS, making it probably one of the most boring pieces of software I've ever used. I check things, run live update manually, run an occasion scan just so I feel like I'm contributing somehow.
2. As others have pointed out, for a host of reasons realtime AV software doesn't play well together. At all.
3. I've never had a problem with NIS and third party software. My computer and internet habits probably account for this. I keep the OS, browsers, AV suite (NIS), and applications up to date and do the occasional tune-up. Hence since I tend to stay out of bad neighborhoods on the net (includes social networking sites), I rarely have the need for third party malware clean-up tools - unless it's cleaning up after some hapless friends and relatives who get infected with malware. (You know the type, the ones who never update their OS, and they still have Adobe Reader v.6 on their machines.)
4. Norton start-up can be disabled, but I can't see why anyone would want to do it. If it's that serious, then uninstall it completely and work from there I say.
5. The ineffectiveness (as state it) of NIS to find malware..........in recent reviews from publications like PC World, I note with interest that no AV software in testing picked up 100 per cent of malware samples thrown at it. Particularly noteworthy here is the reference to multiple realtime AV programs installed on the same machine. If the customer referred to at the bottom of the thread is of the mind that if one AV suite is good, having several is better and between them all it will catch anything, the thinking is fundamentally flawed. As already stated, multiple realtime AV programs on the same machine is a recipe for a whole lot of things that keep the Geek Squad at Best Buy (among others) in business. The way I look at it, there is no vendor out there that can zero defect manage the malware world - a few people have to get hit with it before anyone even realizes something new is out there.
How to disable Norton from Windows start-up is not a craftily guarded industry secret, and there's more than one way to do it. I went offline and disabled NIS a couple years back because it seemed to be causing problems rendering video in Studio v. 10. it was a workaround, but once Pinnacle put out the patch (for a range of issues) it was an unnecessary step. But as I mentioned earlier, I've found no reason to disable it over the past several years. If it's because of conflict with other AV and security software, then either remove it first or remove Norton entirely before installing others.
To come full circle, my recommended solution is to pick one realtime AV program (or security suite), remove entirely any other programs, and stick with it.