Cant upload wp-login.php anymore

Hey,

yesterday I couldn’t login to my admin area anymore, using wp-login.php.
I tried a few thing:renaming my plugin folder, renaming my current theme – didn’t work.
Today I read in the Login Trouble WP Codex, that I should try deleting my wp-login.php – did that and now I can’t upload the new version anymore..
What should I do?

Thank you!