Are you running both the utility that comes with the network card and the Windows built in utility? If so, then you may be connected through one, but not the other. Which icon are you clicking on in the notification (system tray) area that tells you that you are not connected?
There will never be an icon for the router. I asked about an icon for the wireless network card utility. It appears that it is the utility that comes with the wireless network card (again, I did not say router), that is managing your network connections. This will either be the Intel Proset utility, if your computer has the Intel wireless card, or the Dell utilty, if your computer has the Dell wireless card. If you want Windows to manage your wireless network (the better choice in my opinion), you need to open the card's utility and check the box to let Windows manage the wireless connection.
If you can get to View Available Wireless networks, click on "Change the order of preferred networks" in the box on the left. Select your wireless network from the list, then click on the Properties button. A box should open up where you can enter the type of encryption and the network key.
Are you accessing your network or someone else's network? Are you even accessing the internet by wireless? Are you sure you are not plugged into the router by ethernet or connected to a broadband modem by USB? I get the feeling that you have no idea how your network is even set up? Perhaps if you explained your setup we could more easily help.
Without knowing what you changed (did you keep any notes on the changes?) it is awfully difficult to know where to start. You could try System Restore to get back to where you were before you lost connectivity. Note that with your original problem, were you connected by a wired ethernet connection when your wireless connection said you weren't connected? If so, this would explain why you could access the internet even though the wireless was not connected. If you are trying to connect by wireless, you need to unplug the ethernet connection.