In a terminal, type:
lsmod | grep 80211
You should get back something if your equipment is recognized.
If you get nothing, the system doesn't see your wireless. You may need a driver. To go down that road, you'll need to know the chipset used by the wireless equipment. That may or may not require a Windows driver and something like ndiswrapper.
Output should look similar to this (the driver module itself will likely be different):
mac80211 436493 1 ath5k
cfg80211 178877 3 ath5k,ath,mac80211
In my case, that ath5k is the module used. You may not have both lines, you may have them and they're different content, or whatever. But if you have no response back to the above command, you can be sure your wireless isn't recognized.
Start there. At least it will let you know whether or not you're going to need to do some heavy lifting.