User blog:MP999/Source editing not working?

My hard drive crashed a couple days ago, and I had to replace it and restore from a backup. (PSA: Back your computer up frequently and save important files to external sources!). Because I generally upload my thumbnails to here once they're done, the only Death-Battle related stuff I lost was my notes on the next two battles and my One Minute Melee victory images. I can replace the former, and I don't really need the latter.

But now, for some reason, whenever I edit an article, it automatically goes to visual mode, where you make the edits as they would appear on the finished article. Previously, it was source mode, where you had to use ==title== to add a section, and so forth. I found this method to be much easier. The option to switch to source mode is at the top of the screen, but whenever I try to switch, the text is present for half a second before it changes to a blank screen. I am still capable of typing in this blank screen, but I can't see a thing until I preview the finished article. Here is a picture for reference



This is also occuring on the One Minute Melee wiki. Is there anybody who can help me out on this? Is it a wiki issue? Do I need to edit my browser options? I really don't know much about computers. Thanks!

I will reward anyone who can help fix my problem with a thumbnail. That seems to be the best form of currency on this site.