Here's some things to be aware of to login success-
fully:

a. Type your username in lower case letters, no
    CAPITAL letters

b. Sometimes when pasting the password in, a
    space ends up on the end of it which would
    make it incorrect. Make sure you don't in-
    advertently put a space at the end of your
    password OR your username

c. Before logging in, clean out your cookies and
   temporary internet files (go up to file at the
   top of your browser, then choose Internet
   Options to find where you can delete them).

If the above doesn't solve your problem, I'm wonder-
ing if you have a setting somewhere in your browser
that isn't letting you in...

d. Are your cookies turned on?

e. To find out if your browser settings are the
    problem, try to login through Mozilla's Firefox
    browser to see if the problem persists there...
    You can download a Firefox browser here:
    http://mozilla.com