WordPress site won't show up

Do not edit the Twenty Eleven theme. It is the default WordPress theme and having access to an unedited version of the theme is vital when dealing with a range of site issues.

Re-upload a fresh, unpacked, copy of the Twenty Eleven folder to wp-content/themes using FTP or whatever file management application your host provides.
http://wordpress.org/extend/themes/twentyeleven

Then create a child theme for your changes.