Hello Erick,
Lets think:
* You deleted all the files on public_html using cpanel file manager or ftp program
* You uploaded wordpress file name wordpress-3.3.1.zip on public_html
* Extracted wordpress-3.3.1.zip
* https://www.yourdomain.com/wp-admin/install.php
* Provided information regarding database, website, user, password,.. and wordpress installed successfully
* https://www.yourdomain.com/wp-admin/
But, now you can’t login!!!
Why don’t you:
1. Check your database if using old or previous one.
2. If you believe some files are missing copy and replace wp-admin and wp-includes using ftp program or file manager from cpanel.
3. try again eg: https://www.yourdomain.com/wp-admin/install.php
Thnx