Firewalls that apparently don't exist

[mitchables]

Yeah, for some reason when I connect to the 'net on my PC now (I'm on my olds' computer), every time I try and connect to MSN or look at a webpage, it tells me that apparently I'm behind a firewall that doesn't allow direct connection to the internet.

I don't know when it was activated, because it worked last night. :| I can't find any active firewall. The Internet Connection Firewall that Windows has is disabled. I even tried disabling my PC-Cillin Firewall but that's never been a problem before.

I can't find this stupid firewall anywhere, and I don't know when it was activated or even HOW it was activated, being that somehow it appeared between me falling asleep and me waking up.

HELP AN AUSSIE OUT. :'(

[Triple A]

What is the exact message it gives? Type it here and then we can search it on Google to see if anyone else has a similar prob.

[Silent]

Try resetting your modem first of all, but I'm assuming you did that.

Edit: I misread.

[mitchables]

Things I didn't do. :$

But it's working now, so, uh, thanks Silent. :D