Network connection is lost after few hours

Hi, I tested firewall versions 2.3.6 (release) and RC4 during the weekend. With both versions I have the same problem. The network connection is lost after few hours and the connections tray stops responding. After this the computer responds very slowly to commands and only way to resolve this and get internet connection back is reboot.
The connection between ISP and ADSL modem stays on but the connection between the computer and the modem is lost. I’m using Win XP Pro SP2.

The problem is not in the firewall software. I uninstalled the firewall software and the connections tray keeps hanging. I have to do more testing. Maybe Norton Internet Security did something to my computer when I removed it before testing Comodo.

look for an option to STAY Active or PING the server. You’re getting disconnected from the remote server