Removing pppoeconf settings

I was having broadband connection, which i configured using pppoeconf command. now i configured my modem in always on. but i was unable to edit network settings of pc (as now i have to use dynamic ip). so following worked for restoring settings:
To have NetworkManager manage all interfaces without editing ifupdown/interfaces files, this should work.
Check /etc/network/interfaces.

Open Terminal and give command

gksudo gedit /etc/network/interfaces

Remove everything but

auto lo
iface lo inet loopback

Then Check /etc/NetworkManager/nm-system-settings.confOpen Terminal and give command
gksudo gedit /etc/NetworkManager/nm-system-settings.conf
Remove everything but
[ifupdown]
managed=false

Restart computer or NetworkManager service.
From now on, only configure the network using the NetworkManager applet in the notification area (aka system tray).

For more info See: http://wiki.debian.org/NetworkManager