Okay, let me summarize.
I'll give my two computers a name.
LAPTOP:
Can login using Firefox.
Can NOT login using IE 9 for 4 days.
DESKTOP:
Can login in using Firefox.
Couldn't login using IE9 for past 4 days -- but then it started working this morning after I logged in to a different UBB forum using IE 9. Maybe coincidental?
MORE INFO:
On the Laptop, I don't have ANY cookies that match the list that Ruben sent me. I don't think that I've EVER selected "Remember Me" when using that computer (it's my way of security - if I ever loose my laptop, there are very few, if any, passwords/cookies stored on it).
So -- deleting the cookies on the Laptop does NOT assist in resolving the problem.
Next?