Connection to Internet couldnt be established

Hi,

i have just purchased a new Desktop PC. iam using Belkin 802.11g USB adapter to connect to Internet. i have a ADSL wireless modem/router. when i installed the belkin USB adapter, it can able to detect the SSID but the connection to Internet Fails. the “Link information” in belkin wireless utility says that the connection is established from USB to ADSL but there is no connection from ADSL modem to Internet.

Iam using a laptop which is WiFi enabled. i can able to use the laptop without any problem of Internet connectivity.

iam quite confused with the type of key that has to be keyed in as it has got different types of keys such as open system, shared key, WPA,etc.,