I'm looking in two different directions with the following. Toward IP, and toward Apache.
This also assumes the firewall is currently off, and that this is Mac OS X client and not Mac OS X Server. (If you don't know which version you have, then you almost certainly have Mac OS X client. Server costs more. And it's not commonly encountered on MBP.)
Launch Terminal.app from the Utilities folder, and if you haven't already done this as part of your "put all configs back", then issue:
sudo mv /etc/hosts /etc/hosts_save
and create a new /etc/hosts with pico, vim or emacs or another command-level editor and containing the following:
##
# Host Database
#
# localhost is used to configure the loopback interface
# when the system is booting. Do not change this entry.
##
127.0.0.1 localhost
255.255.255.255 broadcasthost
::1 localhost
fe80::1%lo0 localhost
Then:
dscacheutil -flushcache
try a reboot now, and then try the Safari connection again. (Yeah, you might be able to skip a step or two here, but I'm shot-gunning.)
If that connection fails, issue:
apachectl configtest
Depending on your Mac OS X version, you' get a spurious ulimit message +/usr/sbin/apachectl: line 82: ulimit: open files: cannot modify limit: Invalid argument+ (which can be ignored), and then a Syntax OK or one or more error diagnostics. If you get diagnostics (other than the ulimit), post those.
Then post the output from this:
sudo lsof -i -P | grep -i ":80"
Which will usually show what's connected to and listening on port 80.
I'm assuming you haven't been establishing static IP routes or other such. (What
have you been changing here?)