I have a problem with my Panda Antivirus. It does not let me to connect to the internet . I have desactivade the firewall but even that does not work. If someone knows how to solve this problem please tell me!

Did u tried a reinstall of av software?? then stop its firewall again .

The first thing to try is to shut off all other unnecessary applications first (instant messaging, media players, etc).
Or try rebooting your computer first to clear out the memory.
Now if you cannot connect, disable your firewall software (ZoneAlarm, Norton Personal Firewall, Windows Firewall, etc).
Try connecting again and see if it works. If it still does not work, reboot the computer into safe mode with networking and launch the antivirus software manually. Now try connecting again.

If it works, it has to be a startup program or system service blocking it. You may wish to research further into that.
If disabling the firewall works, just add Panda AntiVirus to your firewall's trusted software list to permit the software to send/receive connections.

Hope that helps.