How to get Internet connection working (restarting networking and network-manager does nothing)?

Question

My Internet connection is not working since I restarted my laptop (which is very old). Here's what I've tried:

1. Ran sudo -s then tried /etc/init.d/networking stop:

   * Deconfiguring network interfaces...
   Root@carlos-laptop: ~#
   

2. Ran status networking:

   Networking stop/waiting
   

3. Ran status network-manager:

   network-manager start/running, process 621 
   

4. Running restart networking gives me: restart: unknown instance:

5. I successfully restarted network-manager.

6. Ran /etc/init.d/networking start.

   It says I should instead use the service(8) utility and "since the script you are attempting to invoke has been converted to an upstart job, you may also use the service(8)... ...networking stop/waiting".

7. Tried ifup eth0 and got ignoring unknown interface eth0=eth0

   ifdown eth0 gave: interface eth0 not configured

8. Then I configured /etc/network/interfaces in nano.

   Specifically, I deleted loopback lo and inserted eth0.

   Then I ran /etc/init.d/networking restart. (By this point i thought it would work, but i was wrong.) I got:

   *reconfiguring network interfaces...
   Internet Systems Consortium DHCP Client V3.1.3
   Copyright...bla all rights reserved

   Listening on LPF/eth0/00:90:f5:4d:f8:ed
   Sending on --as above--
   Sending on Socket/fallback
   DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 4;6;7;14;19;11
   No DHCPOFFERS recevied.
   No working leases in persistent database - sleeping. 
   

9. I tried to ping www.google.com and got ping: unknown host www.google.com.

10. Ran dpkg --configure -a which gave:

    Setting up libsdl-ttf2.0-0 (--configure): subprocess installed post-installation script returned error exit status 2
    Errors were encountered while processing: 
        libsdl-ttf2.0-0
    

11. Tried restart networking again:

    There is already a pid file /var/run/dgclient.eth0.pid with pid 1811 killed old client process, removed PID file
    

    Internet Systems ...
    Got the same answer- no DHCPOFFERS received.

12. Started Firefox, went to Google:

    -XML Parsing Error: not well-formed
    Location: jar:file///usr/lib/firefox/omni.ja!/chrome/toolkit/content/global/etError.xhtml
    Line number 23, Column 51:
    <link rel="stylesheet" href="chrome://global/s
    

13. Tried to restart the laptop, and got nothing again.

14. Ran route -n:

    Destination 169.254.0.0
    Gateway 0.0.0.0
    Genmask 255.255.0.0
    Flags metric ref U     0      0
    Use Iface 0 eth0
    

15. Did sudo dhclient eth0, got: no DHCPOFFERS received

16. Restarted again, opened /etc/network/interfaces. It was empty. NetworkingManager.conf is also empty.

I don't know what to do. I am so frustrated right now and have been writing this for an hour on my friend's iPhone. So if you can, help me, thank you.

Answer 1

Paste this into /etc/network/interfaces and reboot the computer:

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet dhcp