Can't get cable modem to connect to PC. I can ping from CMD window, but IE and Firefox don'

I've been online with Comcast, Linksys (cable modem), and Compact to no avail. At first I had no connectivity via my PC. I uninstalled ZoneAlarm and now can ping external sites. But IE and Firefox don't work. I still have DSL, and using the same cords and ethernet plug, I can connect via DSL. Plugging the ethernet cord into the cable modem, I can't connect. Comcast says they can see the modem and everything looks good from their end. The tech who installed the cable was able to connect with his laptop. Windows XP firewall is turned off. Have Spybot and AVG running for antivirus. Nothing running right now for firewall (I'm using my DSL until I can get cable running). I've tried connecting to my wireless router, and can't access the router via IE or Firefox. I've rebooted PC and cable modem dozens of times now. I can repair the network connection and it gets a good IP address per Comcast. I'm at a loss as to where to go from here. Any ideas?

Can't get cable modem to connect to PC. I can ping from CMD window, but IE and Firefox don't work.?microsoft word download

This is basically a network stack problem. IE and Firefox are looking in the wrong place for the connection. The easiest fix is to delete your network adapters from the Hardware manager. (Sounds extreme but its not) Then reboot, let the system find your adapters and reinstall them.

Once that is done setup your connection and you should work.

Can't get cable modem to connect to PC. I can ping from CMD window, but IE and Firefox don't work.?internet explorer download internet explorer

Windows is the problem - it still looks for the old modem's interupt request. I would try to boot windows from the CD with the old modem detached and select repair if it offers that option.