Make sure you're using the correct User Name and Password. See the above question for details.
Use an updated browser. See the first question on this page for details.
Keep your "cache directory" clean. Your Internet browser "remembers" where you've been by storing files in a temporary folder called the cache directory. If this folder isn't emptied periodically, it can interfere with your ability to log in. Here's how to empty the folder:
On the PC:
On the Macintosh:
- Under Tools, choose Internet Options.
- In the center of the window, under Temporary Internet Files, click the Delete Files button.
- Under Explorer, choose Preferences.
- Choose Advanced on the left side of the window.
- Click the Empty Now button under Cache.
Turn off your popup prevention software. Software intended to prevent popup ads may keep you from logging into our site. If you have popup prevention software, please disable it before logging in.