Can't Install wifi adapter. HELP!

I have been unable to install a wireless adapter. I've tried Asus, Netgear, Belkin and at least two others. I use Win 7 Home Premium 64 on a machine that's about eight weeks old. In each case The Device Driver recognizes the adapter and says it's working. It says the driver is the best driver. I live in an RV campground and depend on Tengo Wi Fi service. I connect to the internet with a Wifi Ranger Router using a LAN cable. I have made sure that Wireless LANAutoconfig service is on automatic. I'm not sure what to do about the dialogue in the Log On tab of the autoconfig box under Local System Account (which is checked) that says "allow this service to connect to the desktop". I've left it unchecked because that's the default position.

Yesterday I bought a Netgear N600 Adapter. My Network Sharing Center sees the new adapter after installing the driver, but when I right click to Enable, it runs through a little dance "enabling" but nothing changes. The system "sees" the adapter
but won't connect with it. When I try "connect to the internet" under the broadband icon, I get a box asking for user, password and domain. I have a Tengo name and password but don't know the domain. Is this the info that it wants?

Iv'e tried installing with firewalls on and off. No change.

This stuff should be plug n play, not endless grief. I'm so tired of spending hour upon hour trying to get an adapter to work. Why not just use the router, since it works? That's not the point. Sometimes the router goes down and I need the adapter
to take me to another network. I would love to have this clarified because it seems to me something didn't install correctly on my computer when it was set up. I'm missing a dll or a registry entry. There's a glitch. I have been researching the pages at EZLAN.COM but haven't found a solution.

Help, Please!

The username and password that it is asking for are probably to get into the configuration screen. The default with Netgear should be "admin" for the username, and "password" for the password.

If that isn't what it wants, please could you post a screenshot of the screen that you are getting?

I don't know if you can see this attachment. The smaller box at center screen is asking for username, password, domain name. It comes up when I click on connect to broadband connection.

Thanks

That looks like a Windows connection dialog box. The wireless adapter should have come with some software and drivers. There is usually an icon in the System Tray / Nitofocation area at the lower right of the Taskbar for the Netgear management software. Try using the Netgear software (if active) to connect.