Keep this window open, but disconnect from the Internet right now if you were directed here. (Remember that hi-speed connections are "always-on". Turn off, or unplug your modem or whatever connects you to the Internet.)
OK, now relax. Hackers or network worms can invade your computer in a matter of minutes if you do not have an active firewall. Evidently you're here because you're not sure. Pick the case that applies to you and follow the instructions.
You know that you don't have a separate firewall installed. You don't know if the firewall in Windows is on. [instructions]
You don't know if you have a separate firewall installed. (This case is not too likely.) You don't know if the firewall in Windows is on either.
Go to Start > Programs and see if you find a folder or shortcut for another firewall. You can also look in tray area of the Taskbar to see if there is a firewall icon. If you find one, check the options to be sure it's on. Make sure the one in Windows is not enabled.
If you find one, make sure that it is running and enabled. If you don't find one, make sure the firewall in Windows is enabled. [instructions]
You know that you have a separate firewall installed. You don't know if the firewall in Windows is on.
Make sure that the separate fire wall is running and enabled. Then make sure the firewall in Windows is off. [instructions]
You know that you have a separate firewall installed. You know that the firewall in Windows is not on.
Check the options for your alternate firewall to make sure is running and enabled. Then make sure the firewall in Windows is off. [instructions]