CPU/ABI: Here you can specify if you want your emulator to be hardware accelerated(fast: intel-atom) or not(very slow: armeabi-v7a).
SDcard size: Set the size of the virtual SDCard in your emulator. You need to set it to be able install applications.
Have you tried to delete the MyAvd0.avd file and creat a new virtual device? Maybe it's a name conflict. Try to create a new device with another name instead of MyAvd.