I just installed Ubuntu 9.04 on a new Dell Inspiron 1545 and the wireless network was working. When I went to use it today it wasn't working. When the network icon was right-clicked, the "Enable Wireless" option was not listed. Here's what I've done so far:
1. I went into edit connections and checked that the network can be seen and the WEP key is correct.
2. There in no physical switch on the sides of the laptop to turn the wireless network on/off.
3. The F2 key used to do that when Windows was the OS. I tried every function key alone and also tried them preceded by the Fn key.
4. I tried restarting.
5. I checked the BIos SetUp to make sure wireless was still enabled.

Any suggestions would be greatly appreciated.

Is the card recognized, is the driver loaded?
What is the output from

Laptop wireless went out when my kid hit a bunch of keys.

Running Ubuntu 8.10 on a Dell Inspiron 1545

Wireless button F2 (with the tower icon) did not work as advertised to turn wireless on/off by using Fn-F2 (i.e., holding down Fn key while hitting F2)

Hair tearing ensued;

Ultimate solution: hitting F2 once turns off the wireless connection; but to turn it back on requires holding down the F2 button for a long time, like 30 seconds or a minute

For me, on the 1545, neither the Fn key nor the function key are relevant to turning on/off wireless

Hope this helps somebody.

thanks, Ted... it did help! I have an Inspiron 6000 running Ubuntu 9.04. I was trying to pull up the "run" window using "Alt-F2" and must have accidentally hit "Fn-F2" thus disabling my wireless! After freaking out, plugging in an ethernet cable and finding your post, I was reminded of this hardware feature. In XP with dell-quickset I remember a little logo popping up to let you know the change was made... didn't realize the function keys would even work in Linux! Anyway, thanks!

I have an Inspiron 1501 and have turned off the wireless, yet I have pressed the F2 button for over 2 mins and no luck in turning on the wi-fi. Can anyone help?

Did you tried
fn-f2 ?

many thanks yes i did try fn-f2. is there a device manger eqivalent in ubuntu that i can use to check the status of the wi-fi device?

regards