Created an account here just to let you know this is still an issue: /index.php?showtopic=45863" rel="">https://forum.bitdefender.com/index.php?showtopic=45863
I'm running win7 and have never turned off JS or noticed problems with any other website. Not that I use IE hardly ever, but it works fine when I do.
I ended up uninstalling bitdefender as the hassle was not worth it for me, I think you are probably losing a lot of customers this way so I would recommend you either simplify the page or change the way you redirect to the signup.