cant browse web after updating ubuntu

It looks like your network connection is down. This can happen when it is misconfigured or there is some trouble with the network card. in a normal situation I would give you a command that will output a lot of diagnosis data, but it will be hard to post that here without internet connection.
So I will ask some simple questions first.

Are you connected via a cable or wireless? If you are using a wireless connection, can you connect via cable? Does that work?
How does the Network Manager icon look like? It a symbol in the upper right corner. It can look different depending on the connection status. Here is an example: http://www.multimediaboom.com/wp-content/uploads/2010/11/networkmanagerapplet.png

> Updated to version 11.04 from version 10

So internet was working then. It does update now also or does it work when you to install an application?
Then try what was suggested from the message.
> Clear the "work offline" menu item then try again"
https://support.mozilla.com/en-US/kb/Error%20loading%20web%20sites#w_offline-mode

Future reference.
https://support.mozilla.com/en-US/kb/Error%20loading%20web%20sites
https://support.mozilla.com/en-US/home

after running the updates, my computer will not give me the web browser i am connected to the internet however, i cannnot do anything else because i get the low memory message how can i correct this

To Thomas
Thanks
I also have windows explorer on my pc so am able to access the web.
Connected by cable.
Only enable networking is ticked.

Network manager
Wired Network
Wired Connection 1
Disconnect
VPN Connections
Enable Networking (ticked)
Connection Information
Edit Connections

OK, that show that the wired connection is up. That's good.
Now please click "Connection Information" and post what it shows.

Also as a second step you can test the internet connection by opening the application Terminal (in the Accessories group) and running this command:
ping -c 3 www.google.com

It should give an output like the one below (with some different numbers).
If it does not tell us.

sample output:
$ ping -c 3 www.google.com
PING www.l.google.com (209.85.149.105) 56(84) bytes of data.
64 bytes from ber01s02-in-f105.1e100.net (209.85.149.105): icmp_req=1 ttl=57 time=15.8 ms
64 bytes from ber01s02-in-f105.1e100.net (209.85.149.105): icmp_req=2 ttl=57 time=15.9 ms
64 bytes from ber01s02-in-f105.1e100.net (209.85.149.105): icmp_req=3 ttl=57 time=14.0 ms

--- www.l.google.com ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2002ms
rtt min/avg/max/mdev = 14.029/15.264/15.902/0.879 ms

Connection Information
General
Interface Ethernet (Eth0)
Hardware Address 00:16:17:C3:18:DB
Driver tg3
Speed 100 Mb/s
Security None

IPv4
IP Address 192.168.1.33
Broadcast Address

Unluckily the more important part is the rest below.

Sorry message sent to soon

IPv4
IP Address 192.168.1.33
Broadcast Add 192.168.1.1.255
Subnet Mask 255.255.255.0
Default Route 192.168.1.1
Primary DNS 192.168.1.1
IPv6
Ignored

Put command in search box in applications
result
connection unable to be established
clear the offline menu then try again

Thanks once again for your help
If all else fails I will try to reload earlier version back on 10.10

Ok, it is not a network issue.
Now open firefox, open the file menu and make sure there is no hook before "Work offline". If there is one, click on "Work offline".
Test if the internet works now.
If not goto Edit → Preferences → Advanced → [Settings...] and make sure that "No proxy" is set.

no hook before Work Offline and no edit menu, or other menus at top of screen just message saying cannot establish a connection

There is no menu at all?
Then right-click on a free area in the tab bar and acticate the menu.

Wow at last , thanks so much for your patience Thomas , it took some time, but I finally got a tool bar up and am happily back on ubuntu. Wont miss windows explorer at all. Thanks again.
crissy x