Checkout Page Stopped Working

A couple of days ago our checkout stopped working, it could possibly be ajax but it is quite distressing as no one can purchase anything. The normal sign in section does not appear and the links are unclickable. I have attached a screen shot of what it looks like

It happened suddenly and not while it was being upgraded or another work done to it.

If anyone can help it would be greatly appreciated

checkoutissue.png

Try to temporary switch to the default theme and check the checkout. If it works, please contact theme developers and inform them about this issue

Try to temporary switch to the default theme and check the checkout. If it works, please contact theme developers and inform them about this issue

Thanks, it was the theme that was causing the problem.