WordPress admin page says 'This webpage has a redirect loop''

Hey,

I spent 10 days solidly editing the website for http://www.badtasterecords.co.uk using the ‘Runway’ theme through the genesis framework.

I got everything exactly how I wanted, then installed the Yoast SEO plug-in yesterday, all was fine until I clicked the enable breadcumbs option on the plugin (not sure if it’s related to the problem) but then the site went offline and stopped working. I managed to resolve this through my server (changing all files to 0644 and folders to 0755 as some had been altered) BUT I still can’t log-in via http://badtasterecords.co.uk/wp-admin/- I get the error message ‘This webpage has a redirect loop’ every time.

Here’s what I’ve tried to resolve it:

Manually disabling the plug ins folder in the server FTP (I followed WordPress instructions and renamed the folder ‘plugins.hold’)

Deleting the ‘Runway’ Theme and re-installing it on the server

Accessing the admin section via http://badtasterecords.co.uk/wp-login.php – it shows the login email and password but after entering the details it doesn’t load anything.

I’m seriously frustrated as I can’t seem to find an answer…

Here’s the most recent actions I’ve done to the site prior to it all went wrong :

Installing the wordpress SEO plugin by YOAST (and enabling sitemap.xml and breadcrumbs)
Installing the W3 Total Caches plug in and adding the extra code to .htaccess file

Please help! I urgently want to resolve this.

Thanks!