Seeing how you are running Windows 8.1 you might want to buy/install this http://www.bitdefender.com/solutions/windows-8-security.html because it is tailored for Windows 8/8.1
I hope this helps....
Having exactly the same issue, ticket #2014110616000004 and those guys seem clueless. more than 2 weeks and no response Let me know how did you finally install it?...
Hello,
I think the easiest way to find out if this behavior is indeed caused by the antivirus is to uninstall Bitdefender, then check how Firefox performs and if nothing changes, then most likely the root...
...I have found that the product installed updates every time I reinstalled it, and today it notified me of a product update just after, having finished the annoying service task....
OK so cut a long story short - I was asked to install BD Win8 and found out none of my licenses for BD TS 2015 worked. So pointless. In the call they asked me to downgrade to BD TS 2015!!!...
...To ensure Bitdefender continues to perform optimally, we kindly recommend either temporarily disabling the specific NordVPN modules that may be affecting Bitdefender or, if feasible, uninstalling NordVPN...