Admittedly I'm a reg cleaner junkie, have tried/used many over the years. Necessary or not I still periodically use CCleaner's, Eusing, Registry Mechanic and search (search only) after installs (If I don't just restore Comodo Time Machine snapshot) with RegSeeker. I also used to use MSofts but it isn't available anymore. Anyway, recently I was plagued by some buffer overflow errors for the first time in this XP's +six year life. I only keep a few days of CTM snapshots and was reasonably sure, despite initially thinking the errors were just an anomaly, that they started before my oldest snapshot. Like I always do when having a PC issue, I searched the problem and one of the recommendations was to clean the registry, which I did and the problem has apparently been solved.