Networking Disabled.....

Ok this one is really trivial, but I actually spent aroud half an hour running various commands and then had to google to realize the trouble, so I guess its worth blogging it.

If your networking was wroking all fine and one fine moment you see that the networking symbol on the panel is showing networking disabled.
Then right click on the networking icon , and see if "Enable networking is ticked" ,if no then click on it enable the networking.