ok this is weird
im in a dorm and my computer can see the network but there is no internet
any other laptop can access the net but mine, my lan card is fine my
wireless also connects but still no net. the laptops hd died like  a
month ago and dell sent me a new one since then i cant access the net,
all drivers were installed . i dont know what the problem is, the op is xp home.

The problem might be that your winsock is broken.

Go to this website:
http://www.snapfiles.com/get/winsockxpfix.html


And try the software.

It is called Winsock XP Fix.  It's able to create a back up of your
current settings and it restores the winsock to it's original state. 
Try and see if it works.


Ford

A couple more thoughts for you:

1. You don't have a "Default Gateway" and/or DNS configured. Look at
the following website and compare your settings with a friend's that
does work.

http://www.practicallynetworked.com/sharing/troubleshoot/

2. You may need to use a proxy server. Some networks require you to
use a proxy server to access the Internet. Again compare your settings
with a computer that is working.  Here is how to check proxy settings
in Internet Explorer.

http://support.microsoft.com/?kbid=135982

Internet Explorer 6.0
1. On the Tools menu in Internet Explorer, click Internet Options,
click the Connections tab, and then click LAN Settings.
2. Under Proxy server, click to select the Use a proxy server for your
LAN check box.
3. In the Address box, type the IP address of the proxy server. 
4. In the Port box, type the port number that is used by the proxy
server for client connections (by default, 8080).
5. You can click to select the Bypass proxy server for local addresses
check box if you do not want the proxy server computer to be used when
you connect to a computer on the local network (this may speed up
performance).
6. Click OK to close the LAN Settings dialog box. 
7. Click OK again to close the Internet Options dialog box. 


Those two things are probable causes for your symtoms.  Other things
might be a firewall software (ie. Norton, McAfee, Zone Alarm) or
Windows built-in firewall.  Check out the following link for info on
the the Windows firewall. Try turning it off.

http://www.microsoft.com/windowsxp/using/networking/learnmore/icf.mspx

Can you ping your default gateway? If not then you will not be able to go the net.


Make sure that your your network card is to DHCP. So that you will get
an IP from the server.