Unable to use MS Firewall, even through the control panel

Hello all,

Today I found out that I can't use MS Firewall through control panel. It seems that this service is not working anymore.
Everytime I click on it, it does that sound as if is going to open the Firewall properties but nothing happens. I checked the service (through services.msc command) and it says the firewall is on and it starts automatically.
Also tried the windows Fix It but it remains the same.

If I try to start Firewall with advanced security its gives me this failed to load snap-in error: Ox6D9

Any ideas? Thank you.

[Running a Windows 7 Home Premium x64]

Kaktussoft said:

Did you follow this tips? Trying to turn on Windows firewall, getting Error code 0x6D9 - Microsoft Community

Yes I did, but nothing changed.

Layback Bear said:

What security programs have you ever had on your computer?
What security programs are you using at the present time?
The reason I ask is a left over part of a old security program could be keep Windows 7 Firewall from starting.

I am currently using Microsoft Security Essentials and sometimes I run a full scan with Malwarebytes.
I used to run Avira free with Comodo Firewall but not anymore, since I did a full HD format and new windows installation, a couple of months ago.