Some tips in using Windows Phone 8 emulator

Cannot connect to Internet from emulator
Run this command from Command Prompt

    "C:\Program Files (x86)\Microsoft XDE\8.0\XdeCleanup.exe"

It will remove all virtual network cards and they will be re-created when you start the emulator.

Start emulator without Visual Studio
Run this command from Command Prompt

    "C:\Program Files (x86)\Microsoft XDE\8.0\XDE.exe"
    /vhd "C:\Program Files (x86)\Microsoft SDKs\Windows Phone\v8.0\Emulation\Images\Flash.vhd" 
    /video "720x1280" 
    /memsize 1024 
    /language 409 
    /creatediffdisk "%Temp%\dd.720x1280.1024.vhd" 
    /fastShutdown