I have a broadband cable modem connected via USB to my Windows 2000 PC. I want to connect a USB WLAN to my PC so that my Windows 2000 laptop with wireless card so I can access the Internet via the cable modem.
I have set up a workgroup. But if I set the USB WLAN on the PC to ad hoc it freezes the machine instantly.
Other than that scanning doesn't seem to be able to detect a signal or anything from either the USB WLAN or the card in the laptop... though hardware troubleshooting indicates both devices are functioning.
There are two largely separate steps to building this solution, so start by tackling one step at a time:
1) First, create an 802.11 peer-to-peer independent BSS between your laptop and PC. To do this, configure the USB WLAN adapter and the laptop WLAN card to both use Ad Hoc mode, the same channel, the same SSID, and the same keys (or disable security at both ends until yet get up and running). The steps to do this are different for each vendor; you do not say which USB or card you are using. If you are using two different vendor's products, pay extra attention to making sure these parameters match. When typing SSID, capitalization counts. When entering keys, be sure that both ends use the same format (40 or 128-bit WEP, alphanumeric or hexadecimal keys). Both the card and USB adapter must have a binding to TCP/IP. For now, assign a unique fixed IP address in the same subnet to each peer.
You should get a peer-to-peer IBSS up before worrying about connection sharing. For example, if you assign your PC's USB the IP address 192.168.0.1 and your laptop's card the IP address 192.168.0.2 (mask 255.255.255.0), you should be able to ping from the PC to 192.168.0.2 and from the laptop to 192.168.0.1. Make sure that the card/USB radio AND the network connection are both enabled. If you get stuck at this point and wireless parameters match, then I would suspect the USB or card driver (particularly if you are seeing no signal when using WLAN diagnostics). I would completely remove the network connection and adapter from the affected PC/laptop and reinstall from scratch, paying close attention to any OS-specific directions for the adapter. It often matters whether you run setup before the OS "discovers" the USB or card upon insertion. You will also want to check your USB WLAN product manual for Windows 2000 limitations, since residential products do not always support Windows 2000.
2) After you have peer-to-peer running, you will need to enable Internet connection sharing so that other stations on your home LAN (like the wireless laptop) can access the Internet through the cable modem. If I read correctly, you will be trying to share a USB cable modem connection on your Windows 2000 PC. Select the network connection that represents your USB cable modem and open the Properties panel. Select the Sharing tab, and check the box that says you want to share access to the Internet through this connection. Under the box there should be a list of other network connections - select the connection that represents your USB WLAN adapter. This lets other stations send traffic through the USB WLAN adapter, relayed over the USB cable modem, to the Internet. Be careful not to configure sharing backwards - you must enable sharing on your Internet-facing connection, not the home network-facing connection.
When you enable sharing, Windows 2000 will automatically change the IP address of the USB WLAN adapter to 192.168.0.1. It will also automatically assign IP addresses from that subnet to other stations connected to the USB WLAN adapter. That means you should reconfigure your laptop's WLAN card to obtain its IP address automatically. The reason for doing this now and not earlier was so that you could test your peer-to-peer connection first, without connection sharing. You also didn't want your laptop wasting time looking for a dynamic IP address when there was no other system configured to supply that address before.
At this point, if you are successful, you should be able to ping from your laptop to 192.168.0.1 (the PC) and also to any destination on the public Internet.