wireless network problem

First step is to determine the cause. It could be any number of things. If you can answer a few questions we should be able to figure it out. Post the output from the following commands (copy and past them into a terminal)

lspci -v | grep Wireless

and

dmesg | grep Wireless

Do you know if the access point you are trying to connect to (i.e. your router) is set up properly and works? How are you trying to connect to it?

Does the laptop have a switch to turn the wireless on and off and if so, is it on? Is there any sort of indicator light to show that it's on?

Do you have an icon near the clock that looks like two monitors (it changes to signal strength bars when connected)? If you right click it does it have options for enabling wireless and is that checked? Does left clicking the icon show any networks?

Sorry for all the questions but until we have an idea of the cause we will just be guessing.

Thanks.

pyan@pyan-laptop:~$ lspci -v | grep Wireless
06:06.0 Network controller: Broadcom Corporation BCM4318 [AirForce One 54g] 802.11g Wireless LAN Controller (rev 02)
pyan@pyan-laptop:~$ dmesg | grep Wireless
pyan@pyan-laptop:~$

I' new in ubuntu.before this i'm used windows xp.my wireless device is working properly.After I formatted my laptop and installed ubuntu,I cannot use my wireless connection.
Thanks you for your help.

pyan@pyan-laptop:~$ lspci -v | grep Wireless
06:06.0 Network controller: Broadcom Corporation BCM4318 [AirForce One 54g] 802.11g Wireless LAN Controller (rev 02)
pyan@pyan-laptop:~$ dmesg | grep Wireless
pyan@pyan-laptop:~$

I' new in ubuntu.before this i'm used windows xp.my wireless device is working properly.After I formatted my laptop and installed ubuntu,I cannot use my wireless connection.
What should I do?

Thanks Jim Hutchinson, that solved my question.