When I get home tonight I will amend my signature to include machine specs, but there's little of interest there. I have a home-built vanilla Core Duo 6600 on an ASROCK mb with Matshita DVD-R/W and a LiteOn DVD-R/W, a mix of IDE/SATA hard disks, an external USB backup drive, 2 Gb memory, ATI x800 graphics, Sound Blaster Live! 5.1 sound card, and Windows XP Pro with all updates.
My anti-virus is Norton Internet Suite 2007 (at least until the subscription expires - then I go back to AVG and Spy Sweeper). I do not ever run any kind of periodic cleanup or registry optimization tool - I have found exactly what you're referring to in the past when those tools believe registry entries to be orphaned, remove them, and you only discover the damage at a later time. I have Norton configured to ask me what to do about viruses and trojans, but it has never once found anything more malignant than a tracking cookie on my system since I am also meticulous about keeping applications from untrusted sources. My PC is as clean of malware as I can conceivably make it. I make routine weekly backups of my
I wish I could be more precise about cause and effect, but I often go weeks without using Roxio, so the length of time between what caused the problem and my noticing it is usually too long to make any inferences. I run three different compilers on my system, EDA design tools, CAD tools, movie editing software, music processing, math and engineering applications, Microsoft office, games, digital photo editing - far too much to make an exhaustive list or to try to install/uninstall/check for conflicts.
I do recall two installations in the last month - Pinnacle Studio 10 and Adobe Photoshop Elements 6. Probably a handful of games since my game drive was rendered useless in a firmware upgrade malfunction.
Whatever the problem, when it comes right down to it, the only application that ever seems affected is Roxio. It is the only app that periodically wakes up only to think that it hasn't been properly installed. What I will do for the near future is to record any significant changes to my system over the next few months after I repair Roxio and watch for the failure again. If I learn anything useful, I will report back here. Good feedback is the most useful thing a developer can get to track down a problem.