WordPress 3.6 – Cannot Switch From Visual Editor to Text Editor

Plus, the text you type into the visual editor is invisible until you highlight it with your mouse.

I’ve read other questions about this issue & I’ve still yet to stumble upon a real answer. Most have advised to disable plugins to see if that’s the issue. This is an interesting situation because the site I’m having trouble with is a radio station with two locations & with two different WordPress sites. One of the locations was not working & all of the plugins were up-to-date, the other was working until I updated the following two plugins: Jetpack by WordPress & Tablepress.

So I deactivated both of those plugins, one-by-one, but the problem still persisted.

<img src="https://indy.shine.fm/wp-content/uploads/2013/09/Screen-Shot-2013-09-09-at-9.33.01-AM.png" width="550">

Someone else who was having a similar problem who found a fix did so by clearing the cache of his plugins, but I don’t know how to do that. I’m also afraid of losing any content from the site. This radio station updates their site every day & I need to get it working again asap. Any help would be greatly appreciated. Thanks in advance to all the WordPress geniuses out there! ??