Hi '
This just happened to me and I was able to get past it by doing several hard reboots. I had to fully charge the battery , and after three attempts with increasing intervals of time, the system appearently turned the wireless adapter back on.
After the card reappeared, I was able to find it in device manager again, in my case Intel(R) Centrino(R) Wireless-N 2200 under network adapters . Then a right click, to properties , within properties you chose power Management tab. There you will probably discover that by default the computer is allowed to turn off this device to save power. Uncheck the box , click ok and reboot . Hopefully this will prevent it from happening again.
Hope this helps
Art Master T