Hi Kath!
Welcome to the forum. It sounds like you bought the big eDGe, with the 10.1" LCD (the "EE"), right? If so congratulations on getting a good deal!
There is a physical switch at the top of the EE between the mini-USB port and the SD card slot which turns the wireless on and off. You must have nudged it to the off position.
I tend to forget about that switch because I leave it in the "on" position all the time and use the software to turn the wireless on and off.
Good luck and have fun with your new eDGe!
P.S. The EE does have airplane mode, as asnider points out. The Pocket eDGe does not have the physical switch for wireless that the EE has.