Sometimes Comodo Firewall disables all internet connections after system restart

I’m running WinXP Pro SP2, with BitDefender Antivirus 2008 , with Comodo Firewall .
And sometimes, after a system restart the firewall will block all internet connections regardless of any firewall rules or settings. And when I attempt to disable the firewall, it says it’s disabled but will still block connections.
To fix this, I have to power off my computer, un - plug my cable modem for 15 secs. and then re-power the cable modem and my computer. Then all is well.
Any ideas ?