Let's start with some basics.
Please supply the following info, exact models of the equipment please.
The name of your ISP and country of residence.
Make/model of the broadband modem. If dial-up, please specify.
Make/model of the router (if any).
Connection type, wired, wireless.
If wireless, encryption used, (WEP, WPA, WPA2, etc.)
Make/model of network card or wireless adapter.
Make/model of your computer (motherboard if home-built).
Version and patch level of Windows on all affected machines, i.e. XP-Home SP2.
Also, please give an exact description of your problem symptoms, including the exact text of any error messages.
With the wireless machine connect to the network, let's see this:
Start, Run, CMD to open a command prompt:
Type the following command:
IPCONFIG /ALL
Right click in the command window and choose Select All, then hit Enter.
Paste the results in a message here.
If you are on a machine with no network connection, use a floppy, USB disk, or a CD-RW disk to transfer a text file with the information to allow pasting it here.