I'm a bit perplexed. Every once in a while (couple of times a month, on average?), everything slows to a crawl, which typically lasts for a half hour or so, sometimes less, sometimes more. Everything still works, but very slowly. For example, updating my antivirus, which normally takes a couple of minutes drags out to 10 or 15 minutes. All programs open very slowly, and though they then work at near normal speed, anything that involves what I'll call an interface with the OS, such as a Save As, or Print, or Open, moves at a snail's pace. My assumption is that there is something running in the background that is causing this slowdown. But if I start Task Manager, (which then takes up to 5 minutes to open), it shows nothing running, and if I check the Processes tab, it shows the ever inscrutable "System" using 18% - 25% of CPU time. My guess has so far been that there is something in the Scheduled Tasks that is periodically underway. But I've opened Task Scheduler, and, of course, I find a dizzying list of Scheduled Tasks. Trouble is, I have no idea what most of them do, and which ones are actually needed, versus unnecessary, much less which ones might be causing the slowdown. Does anyone either have some idea what causes this, or, if not, where I might find a useful guide to all of the Scheduled Tasks, what they do, and how essential they are?