On Toshiba laptop Firefox works fine, but IE7 and Netscape quit working. At cable provider's recommendations I have reinstalled both browsers, powered down cable modem and laptop and then rebooted in that order, and switched ends of ethernet cable. None of their tests indicate any problem. They have said it is may be a problem with a firewall. How can I determine which, if any, firewall is running, and what else can I do?