Apple update 10.7.3.
This has apparently caused significant internet connection and internet share errors for Apple computers. You might want to have a look at the downsides of this before downloading. There's a fair bit of stuff on the internet. Easiest way to correct the problem seems to be to go back in time and/or reinstall Lion OS X if that is what you're running. Hope the 10.6.8 for Snow Leopard has no jinxes.