Can’t write new post

I am trying to write a new post on my new blog on my new 2.5 wordpress installation. When I go to the admin screen and click on the Write tab, of course it gives me the option to write a post, page, or link. Clicking on the page and link works just fine. When I click on post to write a new post, nothing appears. No fields, only “WordPress 2.5.1 is available! Please update now.” I continue to click and click and click, and I get no option to write a new post. I don’t get errors. I get nothing. Nothing about the screen changes at all. I’ve tried uninstalling my theme and installing it again, but to no avail.

Just to let you know, I deleted the “Hello” post that always appears with a new installation and new theme. But I didn’t think doing so would render me unable to write a new post.

Can you help me?

Thank you for the gift of your time.