How can I tell if my computer already has a firewall?
If you have Windows Vista or Windows XP Service Pack 2 (SP2) running on your computer, you can check to see if your firewall is turned on through the Windows Security Center:
Step 1: Click Start, and then click Control Panel.
Step 2: Click Security Center, and then click Windows Firewall.
If you have a different version of Windows, such as Windows 2000, Windows Millennium Edition, or Windows 98, you should obtain a hardware or software firewall from another company and install it. You can check the manuals of your home networking devices, such as wireless access points or broadband routers, to determine if they include built-in hardware firewalls. If you don't know if a software firewall is on your computer, you can check in the All Programs folder.
Step 1: Click Start, and then click All Programs. Look for a firewall program. Some common brand names for software firewalls for home users include McAfee, Symantec, and Tiny Personal Firewall.