The first thing you should do uncomment the code in the
../wp-includes/query.php file. That is very critical code.
The source of your trouble is a theme or plugin improperly using the
$wp_query global var. Generally, from my experience, unset or set the value of the
$wp_query global var which bad, very bad, because other plugins that might need to access it and plugin that due will generate this error.
Known plugins and themes to cause this are, theme’s based on the Cherry Framework (Template Monster) and there was a version of Yoast SEO that caused this. Both have been fixed. So make sure Yoast SEO is the most current version. The theme is much more difficult because even though the Cherry Framework has been fixed there are still a lot themes still in use and being sold that still include an old version of that framework.
That said… have you installed any new plugin or change the theme or applied and update to any of those very recently?
Maybe the quickest way to deal with this is to move all (not delete) plugin from within the
plugins folder to a
temp folder. With the plugins in the temp folder, the error may or may not go away. If it does not, then the error is being caused by the theme. If the error does go away the error could still be theme but you should gain access to the site.
You can then move plugins one by one back to the
plugins folder and activate them again. Until you get the error again. The last plugin moved may not be the source or cause of the error but it is triggering the error. Move that plugin back to the temp folder and continue moving the rest.
This should at least get you back up and running. Rutting out the source and cause of the error is much more difficult. I can do this for you for a fee of $60 (payable via PayPal). It should take me only about an hour or so to track down and fix. I will require access to the site via FTP (real FTP not the GoDaddy file manager) and admin access to the site. The login info can be sent via the Contact link at the bottom of the page. Pleaser paste a link to this support forum thread in the message so I can relate the two. Thanks!
Hope that helps!