Page and WP-admin blank after a restoration

Hi everybody,

I’m really desperate and I need your help.

1. I’ve restored my page from a backup through the Backup Guard plugin. It must have been badly set, because it only showed part of the content. At that moment I lost my access to the wp-admin.

2. I’ve contacted my host and they restored the database, we put the new data base data into the wp-config. We linked the new files to the page. Then everything went blank.

3. When I try to deactivate all plugins, the page appears but without any files, just code. The wp-admin then gives me this: “Warning: Cannot modify header information – headers already sent by (output started at /homepages/1/d309401471/htdocs/ProviderRestore/wp-config.php:1) in /homepages/1/d309401471/htdocs/ProviderRestore/wp-includes/pluggable.php on line 1216”

Several webmasters had a look at wp-config, it looks fine.

4. When I activate the plugins, everything is white again. I tried to deactivate each plugin separately, but it doesn’t work.

Could please somebody help, I’m panicking. You can also send me a private message.

Thank you!

The page I need help with: [log in to see the link]