Scan regularly still.
1. Some viruses have the ability to re-install themselves as another one in the directory. For that, I usually scan with Abexo Free Registry Cleaner. You can search for it online.
2. dont't rely only on one anti-virus or anti-spyware. The performance rate for individual scanners differ. You might want to try and perform a minimum of 3 anti-virus scans with different scanner. That is more sufficiently covered.
3. I scan my PC once a week, no matter how safe I think I am. The only safest thing is... like my work PC totally no internet connection. If there's a hacker, must be ghost! LOL!
Other than BitDefender, I am also scanning with Spybot Search & Destroy and also Advanced Spyware Remover.