Cant get to Admin Panel

I was trying to figure out how to change the homepage on my blog, and changed http://mydomain.org to http://mydomain.org/test.html in WP-admin -> settings section. I can’t get into the wp-admin now to change it back, is there a file I can manually edit to change it back?

I believe the part I changed said “My Blog” – http://mydomain.org

I’d do a fresh install, but I don’t want to lose thh 190 posts I have made so far.