You could try a fresh installation of Firefox, if, like me, that's the browser you prefer. I've had to do that more than just a few times to flush out the goobs, especially on my "system managed" rigs at work. If there are bookmarks you wish to keep, just export them first as a single file named like <bookmarks.htm> (I think that's the default name given under Firefox' Bookmarks-->Export menu), save that somewhere on your drive. Next, uninstall Firefox from Control Panel-->Programs. Fire up Explorer or Chrome or whatever other browser remains, head over to getfirefox.com, download and install the browser. When you first run it, it should ask you if you want it to be your default browser. Choose yes, and the other browsers should henceforth leave you be. Oftentimes the old bookmarks will just reappear by themselves. If not, just browse to your saved <bookmarks.htm> file and bookmark that. Presto!
Like I said, I've done this Firefox refresh many many times, both for myself and for coworkers, chiefly to override our network-preferred Windows Explorer browser, since it measurably ran like iced molasses on some of the online databases we used for research. Eventually the network admins cooked up a special dispensation for our department to run Firefox.
Anyhow, that might expel your text-handling gremlins and reel back your margins from the far horizons, Tooseevee. The whole process takes only minutes.