The Speedstream 4300 modem does not support wireless connection; you need a wireless router to connect the computer wireless.
As the system has a wireless card installed DW1506 WLAN half height mini-card installed in it, please get a wireless router at a nearby electronic store at a cost effective price to connect the system wirelessly.
Kindly reply for any further help.
Thanks & Regards,
To know more about Dell Product Support, Drivers & Downloads, Order & Dispatch status -> choose your region US Customers; India Customers. For Dell Support videos click Here.