Odd problems with the site as listed above can usually be resolved by deleting browser cookies.
If you are using Internet Explorer on Windows, you can delete all your cookies by selecting 'Internet Options' from the 'Tools' menu, and then clicking the 'Delete Cookies' button.
If you just want to delete the nanowrimo.org cookie, you should be able to find it in the C:\Windows\Cookies or C:\Documents and Settings\Username\Cookies directory.
Please post in the Site Feedback Forum if you need cookie removal instructions for another browser.