Doesn't connect to internet ethernet or wireless--Ubuntu 12.04

Can you ping 8.8.8.8 from the system?

Thank you for your response: Here is the result:
ceas@ceas-laptop:~$ ping 8.8.8.8

PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.

64 bytes from 8.8.8.8: icmp_req=1 ttl=53 time=83.6 ms

64 bytes from 8.8.8.8: icmp_req=2 ttl=53 time=84.4 ms

64 bytes from 8.8.8.8: icmp_req=3 ttl=53 time=84.8 ms

64 bytes from 8.8.8.8: icmp_req=4 ttl=53 time=85.0 ms

64 bytes from 8.8.8.8: icmp_req=5 ttl=53 time=82.7 ms

64 bytes from 8.8.8.8: icmp_req=6 ttl=53 time=83.6 ms

64 bytes from 8.8.8.8: icmp_req=7 ttl=53 time=102 ms

64 bytes from 8.8.8.8: icmp_req=8 ttl=53 time=100 ms

64 bytes from 8.8.8.8: icmp_req=9 ttl=53 time=84.4 ms

64 bytes from 8.8.8.8: icmp_req=10 ttl=53 time=85.1 ms

64 bytes from 8.8.8.8: icmp_req=11 ttl=53 time=82.7 ms

64 bytes from 8.8.8.8: icmp_req=12 ttl=53 time=102 ms

64 bytes from 8.8.8.8: icmp_req=13 ttl=53 time=83.5 ms

64 bytes from 8.8.8.8: icmp_req=14 ttl=53 time=83.3 ms

64 bytes from 8.8.8.8: icmp_req=15 ttl=53 time=84.2 ms

64 bytes from 8.8.8.8: icmp_req=16 ttl=53 time=82.3 ms

[64 bytes from 8.8.8.8: icmp_req=17 ttl=53 time=85.4 ms

64 bytes from 8.8.8.8: icmp_req=18 ttl=53 time=83.1 ms

64 bytes from 8.8.8.8: icmp_req=19 ttl=53 time=83.3 ms

[64 bytes from 8.8.8.8: icmp_req=20 ttl=53 time=84.9 ms

64 bytes from 8.8.8.8: icmp_req=21 ttl=53 time=82.9 ms

64 bytes from 8.8.8.8: icmp_req=22 ttl=53 time=84.0 ms

^C

--- 8.8.8.8 ping statistics ---

22 packets transmitted, 22 received, 0% packet loss, time 21024ms

rtt min/avg/max/mdev = 82.384/86.327/102.862/6.199 ms

By the way--this problem isn't only with Wicd but also with the network-gnome manager.

Thanks for your help

ok then run:

echo "nameserver 8.8.8.8" | sudo tee -a /etc/resolv.conf > /dev/null

On the troublesome system, then retry the web.

HTH

Hi ,
so maybe it is a problem with your router or ISP provider.
I saw you have pinged successfully google public DNS (8.8.8.8) .
Also you said "However, yesterday, at two different work settings, connection worked fine."

I bet on router or/and ISP provider. Can you reset your router ?
OR
maybe you hacked something to do with nameservers ?
post the ouput of
========================================
cat /etc/network/interfaces
cat /etc/NetworkManager/NetworkManager.conf
========================================

Thanks

on Actionparsnips reccomendation:
I followed the instructions:
ceas@ceas-laptop:~$ echo "nameserver 8.8.8.8"

nameserver 8.8.8.8

ceas@ceas-laptop:~$ sudo tee -a /etc/resolv.conf > /dev/null

^Cceas@ceas-laptop

As you see, after waiting several minutes, I hit ^C, since nothing seemed to be happening.

However, having done this I recovered access to the internet. But Veerry slow. So it helped, but something is still not right.

By the way, today at my work setting, I was able to connect fine.

This is the output to NIckTh's suggestion:

ceas@ceas-laptop:~$ cat /etc/network/interfaces
auto lo
iface lo inet loopback

ceas@ceas-laptop:~$ cat /etc/NetworkManager/NetworkManager.conf
[main]
plugins=ifupdown,keyfile
dns=dnsmasq

[ifupdown]
managed=false
ceas@ceas-laptop:~$

I restared the router, but it made no difference. Still veeery slow.

I thank you both for your counsel. I think we are getting close, but not there, right?

Just to give an idea of how slow the internet access is: I had two 64-bit laptops side-by-side, each with Ubuntu 12.04. In each case i opened Firefox and proceeded to open a page of a news source with many photographs. The computer in question took approx. 30 seconds to open the page. The comparison computer took 5 seconds. I took the computer in question to my work setting and using a different internet provider, the pages open in 5 to 10 seconds.

Thank you for your help.