Problem adding new post , and same with older posts

I have a wordpress.com blog, twenty ten theme, started in the Spring 2010 (not sure of version of wordpress).

Never had any problem adding new posts. I write them in visual, not HTML mode.

Today I typed a post as usual, saved as a draft, hit preview. It looked OK. When I went back to edit, all the type shows up as red dashes, no words. When I highlighted the entire box where you would normally edit the post, a ghost of the white type of the original post is still there. oddly enough there were snippets of HTML in that post (which I never added) that show up.

At some point, I tried to delete the draft, thinking I could just start over. THere was an error going to the trash, it asked me to redo. I did redo, and somehow it did end in the trash.

Now, any new post I start has the same problem.. keyboard strokes get recorded as red dashes…all typing shows up as red dashes. Worse yet, all my old posts have the same problem. For instance if I go to edit an older post, when I open it up in edit mode, I see the same red dashes.

What is going on? Is there a setting that is screwy? How to fix?

PS: tried logging out, and logging in again. problem persists.