On Gus's question - I had something similar but not the same happen a couple of days ago. Sorry if this is too off track -
I have sbcyahoo, and have usually read my mail via outlook express as it is faster for me to delete than reading the yahoo mail page. Problem with that is that my received spam comes through on outlook, although mostly highlighted in magenta.
So a few weeks ago I decided to get in the habit of going to the yahoo mail site to knock off the bulk mail first, and then go back to OE to read the non spam mail. It worked well.
Then I went away for a few days and when I came back I couldn't login to yahoo. Not that I had the wrong password or anything, just that the login in window kept coming back asking me to log in. I finally contacted yahoo, they gave me a slightly different way to access the page ( http://mail.yahoo.com.
) and it worked. However... when I used my old desktop shortcut, it still didn't. I then changed desktop shortcut.
This may or may not be related to yahoo just switching to increased storage size, as that happened in the three days I was away.