A network problem (urgent)

A network problem (urgent)-Linux general technology-Linux technology and application information, the following is a detailed description. Statement: the monks are very busy and stupid. The problem may seem boring to everyone! I hope you will not be enlightened. Thank you!
After Linux is installed, it will always be used for troubleshooting. Yesterday, I heard a friend suggest installing a firestarter and configuring it according to his prompt. I felt good (at that time, I used a Broadband Router at home, and I could access the Internet after I started it .) However, this morning, I came to the organization to open my computer and run pppoeconf ...... I found that I cannot access the Internet (the unit is the type that requires dial-up access, similar to the home broadband ADSL). Well, this is my network condition.
Next we will introduce my computer, a notebook of Asus, a wired network card and a wireless network card. The driver has been installed. I started to suspect that it was about the firewall, and I unmounted it. As a result, I still cannot access the Internet. I borrowed my colleague's computer to ask, dabao suggested that I install a network-manager, but I couldn't connect to the network at this time ...... Ou Kan said that I had too many ADSL settings. At that time, I found that firestarter showed that my computer had ppp0, ppp1, ppp2, ppp3, eth0, wlan0, and pan0. I decided to try it. When running pppoeconf, I noticed two directories:/etc/ppp/peers and resolv. conf. I deleted them directly ...... Then run pppoeconf again. I found a vro and got online again. I quickly downloaded a network-manager, but I still couldn't get online. I uninstalled ppp and pppoeconf, and re-installed it ...... Restart your computer
When I got up, I found that I could access the Internet directly like I was using a route. (at this time, I didn't use a router, but directly plugged in the network cable.) I downloaded another firestarter, the results can be imagined and lost again. Finally, I had no choice but to ask someone else's wireless signal password to access the Internet. According to the explanation on the Internet, the conflict between pppoeconf and network-manager was solved, gedit/etc/NetworkManager/nm-system-settings. managed = true, gedit/etc/network/interfaces in conf, only auto lo and iface lo inet loopback are retained, and then/etc/resolv is deleted. conf, and then sudo/etc/init. d/network-manager restart NM dial-up surfing the internet ......

Now I want to ask you:
1. What is the problem? Now I have PPP1 and PPP0. Will there be more in the future?
2. How can I delete unnecessary items?
3. Can I unmount pppoecon or even pppf with NM?

Thank you. Now I am off duty. I want to go home and think about other issues. Thank you.
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Q: If I installed firestarter last night, why can't I uninstall it? If it doesn't matter, why have I been using it for a long time? I installed a firewall last night and won't be able to access the Internet this morning?