I had Bitdefender 2010 and it was doing a choke and puke on all the PC's I had. Finally af ter opening a ticket after continued hard failures by 2010 Bitdefender sent me a link and said install 2011.
In doing so, my PC has slowed down so bad it's like running on a dialup line.
I won't even bother for a pro-rated refund.
It's safe to say I'll never buy a product from this company again.