Comodo Defense+ & Windows Defender

Hi, I am well aware of the fact that having 2 firewalls installed and 2 anti-virus applications installed can cause conflicts, hence Windows firewall is turned off and I only have the one anti-virus application. But I have both Comodo Defence+ and Windows defender running simultaneously, would this cause any problems? As up to now I have not had any conflicts with either anti-malware app.

It should be perfectly fine.
Windows Defender is replaced by this;
http://www.microsoft.com/Security_Essentials/