What keeps shutting off my PC's (Win XP) firewall?

Factual Questions
1

I turn it on, something later shuts it off. On, off. On off. And thus it goes.

Short of malware, what could be switching off Win XP’s firewall? Could it be ZoneAlarm? I’m trying to run both, as my second router in 4 months just bit the dust.

I’ve scanned with AVG, Ad-Aware and SpyBot. Nada.
Does running Win XP’s firewall provided “good enough” protection from hackers?

2

I’ve read that newer versions of ZoneAlarm do disable the Windows Firewall. This is a good thing… you shouldn’t be running two software firewalls together.

I ditched 3rd party firewalls a few years ago. IMO, the built-in Windows Firewall is more than adequate for most users.

3

Yes this is correct. I have the free version of ZoneAlarm and somewhere it has a check box that says it should disable the XP firewall. It is checked by default.