The other PC in my house runs windows 8 and twitter and firefox sites are just fine on that one.
Mine is still on XP
(ever notice how "XP" could be a "dead" smilie

).
I've been on the Firefox help page several times, but thanks for redirecting me there. In the course of re-reading a few things, I came across the troubleshooting page.
I've been there too, of course, but this time I noticed my Graphics info.
This might be my problem:
a couple items show this message:
"Blocked for your graphics driver version. Try updating your graphics driver to version 9.6 or newer."
I'd rather not update, since last time I did that something went terribly wrong with my PC and I had to roll back the driver.
I figured that they had stopped updating the old ATI cards anways...
But maybe the latest one is okay?
I'll try it and see if it solves anything (or makes it worse

)
...just another lost soul...