Hmmm so to clarify the issue a little:
It sounds like you are using a PC that doesn't have built in wireless.
So you are using a Zyxel USB wireless adapter (model name would help like G-202 or something)
You install the latest application/driver from the site for your product but when you plug it into any USB port, it doesn't detect it.
First I would suggest finding the exact model name, it should be on the adapter somewhere, sometimes the bottom will give an exact model name. This will help us in finding the proper app/driver that you need.
Second I would check the device manager just to see if it shows up in there at all. You can also try uninstalling the USB hubs and then scanning for new hardware as stated above by a previous poster.
Often times these adapters need to be installed in the correct order. Usually you have to install the app/driver first and then plug the USB port in when it asks for it. If you have any previous installations then I would first uninstall anything Zyxel related and start from scratch.
You can use the wired network card (assuming you have one) to get this PC online if you want to try some things directly from the PC online.
Also if you run out of ideas and aren't sure what else to try, you can try running a repair on Windows. It should just reinstall/repair important windows files and keep all your files and apps in place. However backup any important files before just in case ;)
Finally, to use Windows Wireless application to manage your wireless you have to start the 'Wireless Zero Configuration Service'
- Go to Start and Control Panel
- Click on Administrative Tools and Services
- In the Services box scroll down the list of Services (Local) until you find the one labelled Wireless Zero Configuration and double click it.
- In the Wireless Zero Configuration Properties (Local Computer) box change the Startup type to Automatic
- Click on Start and once the service has started click on OK
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