All the files on my computer disappeared?

(I've got windows 8 on a Lenovo laptop)
So my computer was being a little freez-y today. When this happens I usually shut it down, and when I turn it on again everything is fine.
Today when I brought it back, it logged it very slowly and said Preparing Windows instead of Welcome to Windows. Then it brought me to the laptops default background and most of the icons on my desktop were gone and all of my documents have disappeared.
I can't find most of the programs that were downloaded into the computer with the exception of a few random ones--Krita painting software and AVG free for example.
It said that my files couldn t be accessed and I was logged in as a guest, which would be an easy fix except that now my computer says its logged into my account and the same problem occurs when I log out and log back in.
I can't figure out what to do, I tried restoring file history and it said that I didn't have a file history. I don't even have Microsoft Word anymore! Has this happened to anyone? Do you have any suggestions?

Do you do regular maintenance on your computer like clearing your cache and cookies and regularly install Windows Updates? If your problem isn't virus related, download free Ccleaner and have it clean out unneeded junk. When the program opens click Run Cleaner bottom right of page and when that is done click Registry in left hand column and scan there and delete unneeded registry entries, if there are any. Do a virus scan with your AVG. Another free program is Malwarebyes (though there's a paid version also) which most people download and scan in conjunction with (or on its own) their antivirus.