My girlfriend's MBP (2007) sometimes stops being able to find sites through DNS. She'll be browsing just fine and then when she goes to hit a new site it will say "Looking up [web address]" in the status bar of her browser indefinitely. She is still able to connect to the WiFi through our AirPort Extreme and if she restarts the base station it will work fine for her. Sometimes this happens 4 or so times a day. Has anyone experienced anything similar? Are there any details that would help diagnose this?