Bitdefender Antivirus Plus 2012 Compatibility

I have recently had some issues with malware and have been unable to repair or restore my PC to a designated point. I have therefore attempted to re-install Windows 7. All was going well until entering the activation code. I gave remote access to Microsoft and cutting a long story short, I have been conned by the vendor from whom I bought Windows 7 from in the first place and the Windows 7 code which I had previously used 2 years ago to install it on to a brand new PC has apparently been blocked because it has been subject to multiple use. Unsurprisingly the vendor has declined to offer any help and so at Microsoft's request, I've provided the vendors details to them to deal with as they see fit.

That has not helped with my problem. Whilst I've been able to restore everything on my PC, I don't have a Windows 7 activation code. If I had been in the US, Microsoft would have provided me with an activation code for US$40. However, because I'm outside the US, they say it will cost me the equivalent of US$140 to get my Windows 7 activated and then only with a 3 month guarantee.

Microsoft say they don't offer Windows 7 for sale anymore and I've also had issues with Windows 7 before. Therefore after some deliberation, I've decided I will give Windows 8.1 a try. However when running a compatibility program, it suggests my Bitdefender Antivirus Plus 2012 is not compatible. I've been advised I would need to upgrade to 2014, which is compatible. I was also told that I could download it and install it and then use my exisiting product key to activate it. I was told that I could do this at no extra cost

Where should I download the Antivirus 2014 from? When I have clicked on download, I am presented with an empty white box and nothing happens. When I have clicked on renew and upgrade, there is no option to download this without making a payment.