The other day I opened up firefox and for some reason every single character appeared as a box with numbers in it, there was not a single letter that was still in english. Everywhere a letter should be there was just a box with a number in it. I wasn't sure how it happened, I had just recently used firefox without a problem and I'm sure I didn't go to any sites that would give me viruses. I spent a while searching for a solution to the problem, but I couldn't find a single thing anywhere about the problem I had. There were a few things I found for problems somewhat similar to my own telling me to edit something in my about:config, but those solutions didn't work for me because it's impossible to find anything within the about:config when everything appears as just boxes with numbers. I backed up all of my bookmarks, then uninstalled firefox and made sure that everything was delted. I then I reinstalled it but the problem was still happening. I also tried running a virus scan with Microsoft Security Essentials and Malwarebytes but neither of them found anything.
At some point I ended up restarting my computer, but things only got far worse at that point. When I got to the login screen all of the words that should have been in english including my account name were instead just a series of random symbols. It's not boxes with numbers in them like it was when the problem was only happening with firefox, but instead there are x's, triangles, circles, boxes, check marks, semicircles, etc. For the most part nothing is readable any longer such as file and folder names, the things in my start menu, the things in the control panel, and even the date and time in the corner of the screen. There are some things that can still be read in english though, such as the names of programs in the task manager as well as a few things in the control panel.
Because my laptop also has Windows 7 I was able to use it to help me navigate through the control panel to find the language settings, but nothing I could find in there fixed this problem. I went into region and language, and under the keyboards and language tab everything was readable in english. English was chosen as the display language, and there were no other options available to change it to. I then went to install/uninstall languages, and clicked uninstall display languages. English was the only language present and I decided to uninstall and reinstall it to see if that worked; however, there was no option to uninstall english. So, instead I decided to use windows update to install french. I then changed the display language to french, but that only changed the words I could still read in english in the keyboard and languages tab to french, it didn't change everything else.
I'm not sure what else to do. I tried running a disk check on my hard drive and made sure to check for bad sectors, however, no problems were detected. Does anyone know what might have caused this and how I could fix this? If I'm unable to get it fixed I plan to format my hard drive and reinstall windows. Before I do that though there is some stuff I need to back up, but unfortunately it's tediously difficult to locate the files I want to back up when I can't tell what any of the files or folders are called. I'm really hoping that I can find a way to fix this problem because it will take an incredibly long time to locate any of the files I want to back up, and in a best case scenario I'd maybe be able to find 50% of the files I want to back up.