Macbook WiFi off and won't turn back on
I have a 2008 Macbook (the first gen aluminium one) and it is running Lion, and has been running Lion with no problems since it came out (last yr?). Today I turned on my laptop and the WiFi is switched off. I tried to turn it back on but the macbook won't do this. I have been in network settings and tried to turn on WiFi there, but again it is not happening.
I saw a similar thread on some other forums about this problem, but the fixes they suggest (set up a new connection, eg "WiFi2" and deactivate the old one) don't work.
I have no idea why this has suddenly happened, but worse I have no idea how to fix it. Any help is appreciated.
Thanks
MacBook, Mac OS X (10.7.3)