I'm running Windows Vista Home Premium on a laptop, and every now and then (eg. when I start an online game or even Skype) I get a Windows Firewall message, giving me the options to "Keep Blocking" or "Unblock". Again, I say - it's not every time - just sometimes but enough to be annoying.
I have the Windows Firewall OFF as I operate behind a router so don't need it. I don't have any other firewall software installed.
Does anyone know what is causing this behaviour?