Bunch of people with similar problem and different fixes they tried here... would prob try a bunch of these if U haven't:
https://discussions.apple.com/thread...rt=30&tstart=0
And if none of that works I would prob just do a "clean restore" of the comp and stuff
Or you can try to install the beta of the NEXT OS X to see if there is maybe a dumb glitch in OS X Mavericks... You can download it here... it is really nice also
https://appleseed.apple.com/sp/betaprogram/
Does it happen just at your home wifi or other places... do you have one of those free cable WiFi networks you can try to connect to to see if those work fine