Can't Log In or View my Blog

I installed wordpress and everything was working fine but now when I try to login, it does nothing – no error msg, just clears out my password and stays on the logon page. When I try and view my blog it just shows an empty white page.

I have tried everything in the instructions at http://codex.wordpress.org/Login_Trouble and nothing helped. However where it said “Check your wp-config.php file. Verify the DOMAIN_CURRENT_SITE value.” it didn’t have anything saying DOMAIN_CURRENT_SITE and never has had.

Initially I was having the problem from one computer but was still able to login and view the blog from a 2nd computer, however I now can’t login from the 2nd computer either and have tried a third computer and can’t login from it.

My blog is at http://www.gethelpfordepression.info/blog

I changed themes, installed the sociable plugin and changed the permalink structure before the problem happened, but have followed the instructions about renaming the theme folder and deleting the plugins and it didn’t help.

The problem exists on multiple operating systems and browsers.

MySQL version is 5.0.67-log
PHP version is 5.25

I noticed when I go to http://www.gethelpfordepression.info/blog.wp-admin it automatically redirects to http://www.gethelpfordepression.info/blog/wp-login.php?redirect_to=http%3A%2F%2Fwww.gethelpfordepression.info%2Fblog%2Fwp%252Dadmin%2F&reauth=1 . I don’t think it was doing this previously when the login was working but can’t be sure.

Would appreciate any help anyone can give me.