I\'m not able to see any of emulator in VS 2012 express for windows phone. My system has all requirements to run an emulator. previously I was able to debug on emulator. Af
In addition to Daniel's answer, you may need to then manually repair the emulator install from programs and features in control panel.
Maybe you could fix this issue by deleting this folder:
When you use Visual Studio 2012
C:\Users\<username>\AppData\Local\Microsoft\Phone Tools\CoreCon\11.0
When you use Visual Studio 2015
C:\Users\<username>\AppData\Local\Microsoft\Phone Tools\CoreCon\12.0
Then open VS2012 or VS 2015 again.
If not repairing is always recommended