There are two parts to your question:
1. Emulator not working : HAXM is not working and emulator runs in
emulation mode
This one is already answered here: How to fix: “HAX is not working and emulator runs in emulation mode”. It was just one search away.
AND
2. “Hello! World” not showing
That is because your emulator does not run at all. (Provided your code is sane)
Just run it on your physical device (I hope you have one) and see if the string displays.
Just wondering, what so complex in this which made this question deserve a bounty? 🙂
solved Android hello world app, can’t see hello world string on device