wireless network notworking

I have just newly install my first Ubuntu 8.04 LTS on my laptop Compaq Presario V3000
I have complete install/update all package
My wireless network didnot work at all
I have alreay try to follow the troubleshooting instruction and more confuse

SO I have check lspci and thw wireless interface shown
Intel Corporation PRO/wireless 3945 ABG

SO I have check driver by lshw -C network with the result come out as below

 *-network
       description: Wireless interface
       product: PRO/Wireless 3945ABG Network Connection
       vendor: Intel Corporation
       physical id: 0
       bus info: pci@0000:05:00.0
       logical name: wmaster0
       version: 02
       serial: 00:1b:77:29:25:b0
       width: 32 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list logical ethernet physical wireless
       configuration: broadcast=yes driver=iwl3945 latency=0 module=iwl3945 multicast=yes wireless=IEEE 802.11g
  *-network
       description: Ethernet interface
       product: PRO/100 VE Network Connection
       vendor: Intel Corporation
       physical id: 8
       bus info: pci@0000:08:08.0
       logical name: eth0
       version: 02
       serial: 00:16:d3:a0:8b:ad
       size: 100MB/s
       capacity: 100MB/s
       width: 32 bits
       clock: 33MHz
       capabilities: pm bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=e100 driverversion=3.5.23-k4-NAPI duplex=full firmware=N/A ip=192.168.1.3 latency=66 link=yes maxlatency=56 mingnt=8 module=e100 multicast=yes port=MII speed=100MB/s

It look like the wireless interface autonegotiation not "on" yet
So I try to config the interface by Networks Tool but always get the answer " The Interface does not exit "

Then I have try to manually connect the wireless network but still not work

Please help me !!!
What to do next