Problem accessing by machine name or IP address -- localhost works fine

I'm trying to access a local installation of Apache from the same
machine. The machine's name is fred and IP is 192.168.1.100. If I
ping fred I get the correct local IP back (192.168.1.100).

When I type http://localhost into a browser, I see the default page.
So far so good. But when I type either http://192.168.1.100 (the
machine's local IP address) or http://fred (the machine's name), the
browser just hangs. Obviously, there's something wrong with my network
setup.

I've temporarily disabled the ZoneAlarm firewall and Windows XP SP2
firewall is also off.

Any ideas?

Might or might not be the reason, but Apache can be set to use named virtual
hosts, in which case the url you type must be what Apache expects it to be,
or else (depending on the config) you may get a default website, or nothing.

This mechanism is used on systems where several websites reside on one IP
address. It wouldn't normally be active on a single site, but might've got
turned on

Thanks for the reply. Virtual Hosting is not turned on, so I guess
that's not the explanation. It had been working just fine, then
started doing this. Not sure what changed. I wasn't doing anything
intentionally different.