There can be two issues:
One:
Windows computers usually call the local network WORKGROUP.
Are you able to connect to the unprepared Arduino Yun at all?
If not, then change your WORKGROUP domain to local. That might work.
I have little experiences with Windows, we only work on Linux and OSX.
If you can access the unprepared YUN, but the hybrid.dmg image does not work, try the following:
Once you have prepared the SD card and you could successfully reset the Yun with the image found on this SD-Card, the Wifi-Reset Button is not working anymore.
If you have no access to the Arduino Yun anymore you should do the following:
- Remove the SD-Card and write the hybrid.dmg image on to the SD-Card again.
- Insert the SD-Card in to the Yun power it up. Your Yun should now open an Arduinoxxxxx Wifi hotspot.
Configure the Yun to your local network and you should be ready to go.
If this does not work. Power up the Yun with no SD-Card, once the White LED glows, push the reset button for 10 seconds. Now you should be able to access the Arduinoxxxxx Wifi hotspot.
Insert the SD-Card and reset with the image form the SD-Card.