Hello,
have a few questions.

Does everything in Avast Internet Security work COMPLETELY with Windows 7 64-bit ?
I mean , the sandbox & firewall & safezone & and EVERYTHING in Avast IS.
A: Yes, it does.

Is the Avast firewall alone not able to protect your computer ?
A: Avast Firewall is able to protect your computer together with other real time shields.

And , i know the Avast firewall is compatible with the Windows fire wall , but why ?
Why not just switch it off automaticly if Avast gets installed ?
A: Avast doesn’t turn off another operating system components if it is not necessary.

It is only more recources on the computer if you run 2 firewalls.
A: Not really.

Is Avast firewall not 100% a complete firewall ?
A: It is compatible firewall. What it does is checking packets going through the network interface.

And if i turn off Windows firewall , and only have Avast firewall , am i still just as secured as when i have both the firewalls on ?
A: yes, you are if you run all the avast shields as well.

And if i am , then why does the Windows firewall not get switched off by the installation of Avast ?
A: see above.

And why does Avast firewall only scores 15% on matousec ?
A: as far as I know these tests are done only with avast firewall turned on and other avast shields are turned off. Avast Internet security must have everything turned on for reliable computer protection.