All software reverts to start, not sure what happened

Question

This is hard to explain since I am unsure what is actually important. Christmas eve our power went off. (this may have nothing to do with what happened) I have a battery back up. When the power went off I shut down the computer and all peripherals. The next morning we turned everything back on and it appeared normal. I personally did not use the computer until later in the day. My son tried to access a web site but since my backup software was running, it took too long so he left it. Later in the day he accessed a web site and all seemed normal to him. Another son later accessed his email (both of these are not apple mail users) He also accessed Skype and thought he had exited it. Later in the day I was going to check my email and skype was still not shut down. I forced it to quit. The desktop looked normal. All my icons were where they should be.
At one point, not exactly sure when, I had finder open and somehow inadvertently dragged my personal home folder out of finder and it went "poof". So my home folder did not show up on the left of the finder window. I opened the Users folder and picked my name folder and drug it back. (This may be the problem)
I tried to access my mail and it took me to the set up as if I had never used Mail before. I then restarted the computer and when it came back up all the icons that had been on the desktop were gone except the HD and my two back up discs. Any software I have tried to open is as if it has never been used. I had almost 10,000 photos organized in Lightroom and it is now empty. The photos are still in the pictures folder, but not in Lightroom. Same with my genealogy software, all addresses are gone from my address book, all history and bookmarks in Safari. As if it is a new computer.
I have repaired permissions, restarted several times,removed Turbo Tax (which I had installed yesterday) removed Skype which my son had used. Started up in safe mode. It is as if I just began using the computer yesterday. No logs, when I open finder it goes to icon mode and I change it each time but when I close and reopen it goes back to default.
It has to be something simple, doesn't it? I hope this makes sense to someone.
Thanks
Judy

Answer 1

If you want to play it safe, and you have an external drive, you may want to drag that folder with all your data to the external drive as a backup. It would be bad if you did something that caused you to lose that data. If you already do backups using Time Machine (or some other method), that's great; you should be fine. If you don't do regular backups of at least your user data, you should.
To get things back to the way they were...
Open a Finder window. Click on +Macintosh HD+ in the sidebar. Over to the right, you should see a folder called Users. Open that folder. For every user account you have on that Mac, there should be user home folder (plus one called Shared ). Is there one there now for your user account (with your user account short name)? When you moved your user account folder, the system probably created a new one. If so, look around inside to make sure it does not have any of your user files.
I have not had a need to do this myself, but it seems to me you will not be allowed to directly replace the new user home folder with the old one, because there are files inside the new user home folder that are now being used (because you are logged into that account). So I would create a new folder in the Users folder, and name it something like Temp. Drag that new user home folder to the Temp folder, so that it is out of the way.
Open a new Finder window that shows your original user home folder in the Applications folder. Drag your original user home folder from that Finder window to the Finder window that shows the Users folder. Your original user home folder should now be where it was previously located.
Restart your iMac. Hopefully, it will start up and log in using your original user home folder. If it works, you can delete that Temp folder.