Weird behavior of template

I created shop based on Bikestore some time ago. Everything was working, but now I have several issues

1) On some pages "shopping cart" lightbox is showing, on some pages not.
2) The same with Login. I installed SClogin - to login with facebook and JFCB - on some pages I see "classical login box", sometimes there is "SClogin box"
3) When I add dvd to cart, it stays in cart. When I add ebook, I still see only first product added.
4) Moreover when I try to add training program or software, I see only empty cart!!!

My shop http://shop.volleycountry.com

I am really desperate. What am I missing???

It seems like something messes up with JS libraries and jQuery doesnt load. Check if any 3rd party plugin does this by enabling and disabling all plugins on your site and testing if it works ok.

There must be javascript conflicts in your site causing some scripts stopping working in some pages. @Cyberek is right, follow his suggestion to sort it out yourself.

I disabled all the plugins, uninstalled JFBC.. but there are still errors.

In fact there are more errors... (I do not use any SEF component)

I can not remove product from cart.
Once I add training program to cart I am redirected to /training-program page, but I see the cart???

Would it help to change the template? Upgrade Joomla, VM?

Even better, since I disabled all the plugins and wrote my last message, the system log me out...

Now I see
JAuthentication: :__construct: Could not load authentication libraries.
And I can not login to the site in backend! How can I fix it?

Thanks a lot for help

Just an idea for you to be able to login back, use phpMyadmin to access your database and change status field in Extensions table to 1 (from 0).

Ok. I fix my login problem in database

Just an idea for you to be able to login back, use phpMyadmin to access your database and change status field in Extensions table to 1 (from 0).

I'm stuck, when I go into phpMyadmin -> the database -> field: extensions: ??? I cannot find a "status" field and thus cannot toggle it.

FYI my host is Bluehost, I'm using Creativity template, joomla 3.0

I think I was wrong, the field name should be "state" instead, look it up in extensions table.