Problem with wireless network adapter

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http://crunchbanglinux.org – Hi, I bought a USB wireless adapter that uses the Realtek chipset RTL8188CUS.I saw that the drivers are already installed in the "Realtek-firmware" package.So i put the adapter in and it is recognized by the sysytem.I go to the network manager applet and I click "Create new wireless network", than i put in the network name and the WPA password. And here comes the trouble. It says it's connected but if I open the browser, it can't open any page.Even if I try to refresh synaptic software sources it can't refresh them, as if I'm offline.What can I do?Thanks (HowTos)