I cannot access my Appache when the computer is connected to internet

[Guest_imported]

I installed Apache on my Windows XP, and it had been working well. Recently I connected my computer to internet through cable (a medium-speed version). Since then, when I openn the browser and imput "localhost", I would get "http 500" errors that says "The page connot be desplyed". When I disab "Local Area Networking" to disconnect from Internet, I can access localhost again. The same situation occurs to IIS also.

Could anybody tell me what's wrong? Thanks!

 

[RhythmAce]

Use the same IP address your ISP gave you for apache to Listen to. On most systems "localhost" resolves to 172.0.0.1 which is the loopback device not eth0 or your ethernet card. Check to see if "localhost" was changed from that IP. If you were given a machine name, that should resolve to your new IP. If apache is setup to Listen for ALL addresses on port 80 (the default), then you should be able to type either "localhost", your IP or your machine name and get to your web server.