there's some traffic my computer i can't know from where !

Have a look at the output from process monitor from sysinternals

Process Monitor

or install Comodo firewall and check the live stats on I/O and block the ones you don't want

Firewall Antivirus Software Free Download from Comodo™

You can keep what you have and there are a lot of other free firewalls, I just gave you what I think is best.

Here is our list of free software.
Comodo is a good firewall
FREE Great Programs for Windows 7

I would not use both at the same time. Use Comodo Anti Virus and firewall if that makes you comfortable. I prefer Security Essentials, Malwarebytes and the Windows Firewall, however.
Whatever your decision, use Malwarebytes.

To watch network traffic, and to find out where it is coming from, as in which program is sending this data, where is this data coming from, what port is it using to send the data through, what country is it sending my data to, etc. You need a packet capture program.

There are many, but the best is Wireshark (imho, of course). This program allows you to see everything that is happening on your network. However, it does require some understanding of network protocols in order to use it. But even if you're not familiar with network protocols, you could still just watch the HTTP traffic on your computer, and see if anyone from an foreign country is sending data to or from your computer.

Another great program, which doesn't really have any prerequisites is NetLimiter, this program allows you to see, quickly and on a simple screen, which programs are sending out/receiving data, and where that data is going. Here is an image of Net Limiter:



Here is an image of Wireshark





A good firewall program would, of course, allow you to do much of the same. However, if you want to Go Deep then Wireshark is what you want.

It's funny you asked this question, because I was just working on a script that will help you locate malicious URL's quickly without having to know network protocols and all that stuff. I'm going to post it to this section of the forum soon, so check back in this section if you're interested

Glad that we could help. You will like that firewall. Use the list that I gave you for other great free software.

If you're curious about the connections and want a quick view of everything, you can d/l TCP View

TCPView for Windows

TCPView is a Windows program that will show you detailed listings of all TCP and UDP endpoints on your system, including the local and remote addresses and state of TCP connections. On Windows Server 2008, Vista, and XP, TCPView also reports the name of the process that owns the endpoint. TCPView provides a more informative and conveniently presented subset of the Netstat program that ships with Windows. The TCPView download includes Tcpvcon, a command-line version with the same functionality.