Ok lets get started:
Step 1. Look at the hold switch. Make sure that the hold switch is on the off position. To be sure that it is correctly at the right position flick it to the on and then to the off.
Step 2. This does not solve the problem? Ok we have to continue. Now we are going to reset the Zune.
Hold the Up-Button and Back-Button together for 2-5 seconds until the screen turns black.
3. That was all. Now you have to wait 5 seconds and then your zune should be back.