Admin is not working anymore

WordPress admin was working fine on the 14th when I added a bunch of posts.

Now nothing is working. I am auto logging in with IE7 but no changes take effect. I cannot change the password, how many posts are viewed, edit a post, delete a post, write a new post, etc. I write a post or edit a post (or one of the other admin changes) and click save or publish and it goes to either a blank page or says the page cannot be found and the changes do not take effect in the blog.

I cannot log in with Netscape, it just refreshes the log in page. I also tried sending the password via the “lost password” link, but that isn’t working either.

Firefox logs in but has the same issue as IE7 – nothing is editing.

I have not changed anything since I uploaded those posts on the 14th and another administrator on the account – in another state, thus another computer, network, etc. – is having the same problem.

Does anyone have any idea why this might be happening or more importantly, how to fix it?

EDITED: BTW, I have a different WP blog on a different site that does NOT have any problems. Everything is working fine with IE7 on that blog.

Thanks,
Krisann