Disable K2 component

I am using the Churchly template on Joomla 2.5.14.

I don't want to have a blog component, so I want to remove or at least disable the K2 component. For this, I have disabled the K2 component via the Extension manager (see attachment). But the moment I do this, the website becomes inaccessible. Once I enable it, everything works again.

You can see the error page here: www.maaikehartog.com/testm/ . Normally, there should be a login page here, because the website is under development.

How can I disable/remove K2?

Well to remove (turn off) k2 you first need to remove all menu items, modules, plugins related to it. For example you home page by default is of type K2->Categories so it normal that you get server error or page not found. You would need to change its type to some native joomla type like Featured Articles