you asked about “recover it”. Well the good news is you only erased the default “blink a LED” application that a standard board comes with. What you need to do is write your own app and deploy it from Visual Studio. If you create a new project for Panda II, the default project template has a blinky LED so just deploy that and you should see the exact same app.
As Gus said, go through the examples and you’ll understand Fez/netmf pretty quickly. But remember, netmf on its own is NOT real time. Do a search on encoders on the forum and you might get some good tips.