might have information about that chipset if it really is 4965agn.
You should try to verify the chipset with lspci:
Search for lines that talk about wireless devices - the device information should be there. Your kernel version you can see with
if you happen to need it.
If the light doesn't come up, it almost surely means that there is no driver (kernel module) for your wireless card loaded. Make sure what chipset the card really uses, then search for what Linux driver (kernel module) it should be using, and see if you have that module loaded:
lsmod |grep modulename
if not, try to load it:
sudo modprobe modulename
If it says there is no such module, it's not in your kernel. Either find out how to install it, or if you can't find a native Linux driver, resort to ndiswrapper (don't, if you can find a native driver): it's a piece of software that you can use to wrap Windows drivers for wireless devices so that the hardware works under Linux. A little more complex than a native driver, but if it works, it's good. Namely you need to install ndiswrapper (use Ubuntu package manager Synaptic) and ndiswrapper-utils, then download correct Windows drivers for your card (an .inf and a .sys file) and run
sudo ndiswrapper -i driverfile.inf
to install them. After this make sure ndiswrapper module is loaded and you should be good to go.