My anti-virus software can not access Internet

[Kishan]

Hello,
I want to install a new anti virus but every time I encounter a problem.
At first I wanted to install BitDefender (free version), but the update, it tells me that the Internet is lacking.
So I uninstalled.
Then I installed Avast (always free), but this, in the updates, it says it does not detect a connection.
This also uninstalled.
I eventually went to install Antivir, which requests a connection from the installation. It said he also found nothing.
I do not know what to do, I tested with wireless internet and cable, I cleaned the registry (I do not know if it is useful). The Windows Firewall is not activated.

And here I need help.

For info, I have Windows XP SP3.

Thank you

[EINSTEIN_007]

See similar threads: http://forums.techarena.in/security-virus/921546.htm
Applications cannot access internet

[Kishan]

There is always the same problem with AVG Antivirus ..
Mmmmh. I do not understand!
Going to check the links now.

[Zachary]

Post a HijackThis Log report here: HijackThis - How to use HijackThis? What it dose?