New to Windows 8 but installed "Bitdefender Windows 8 Security" - alas Firefox (latest release Ver 18) screeched to a halt.
Had some other Virus checkers on system, but all disabled. Removed all traces of other virus-checkers and updated Firefox to latest Beta - and all seems to be OK now.
However:-
Action Centre within Windows 8 has a permanent message that BitDefender has both Virus Checking and Firewall switched off.
BitDefender indicates that both are on - and they do seem to be on as an incoming virus has just been zapped.
Disappointed by this warning message however. The messages in Action Center don't seem to have a time-stamp - this is poor - maybe they are historic!!!
First time user of Bitdefender - retired from IT - remember the days when mainframes had 16K main storage.