Have you run a virus scan? If not, you should. It could be something you did accidentally, or a number of other things.
When you've gotten your system back like you want it, I urge you to get yourself an external hard drive and a good 3rd party backup program. You can set it up to do everything automagically at the time and frequency of your choice. 1 TB external hard drives are about $50 these days and a really good FREE backup program is the Easeus Todo Backup Free. That can save you a lot of time and frustration the next time something like this happens. Sooner or later it happens to all computers for one reason or another.
Good luck.
In all the years that I have been on computers i do not recall ever losing a Folder until recently. it happened to one of my folders that hold a couple of my photo editing programs. I couldn't find it. Why and what would cause one to lose a folder or folders? As of now that is the one concern i have, but who knows there may be others, once i have to go to them. I did a search for a recovery program hoping that I can find it or them. It was a free one called "Recuv" or something like that. I ran it and it found the one I was looking for. The first thing that came to mind was maybe a virus.

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