cannot login at all

I cannot login to two of my websites. This problem has been going on for days. I have re-installed Version 3.1 several times, on both sites. I have removed plugins, I have checked the wp-config.php files, I have reset my password in MyPhpAdmin. I have asked my Hosting server for help.

When I try to login using my actual password, the login page goes blank and then returns. If I put an incorrect password in, I get the screen asking if I want to get a new password. I enter my email address, or user name, and I get the screen saying an email has been sent. No email ever arrives.

I have tried changing my email address in MyPhpAdmin. It makes no difference.

I would be most grateful for any further advice. The urls are:
http://www.being-in-voice.com/blog
http://www.blog.thundersmouththeatre.com