How to resolve 'Emulator: PANIC: Cannot find AVD system path. Please define ANDROID_SDK_ROOT'

I solved my issue like this...

Go to 'My Computer'-> 'Properties' ->'Advance System Settings' -> 'Environment Variables' -> inside 'System Variables' add "ANDROID_SDK_ROOT" or "ANDROID_HOME" and inside this set the path of your AVD.

After that Restart your Computer. You must Restart your computer, otherwise it won't work.

This method worked for me, situations may be different in other cases. Look here for more information.

It may be caused by improper SDK location.

Open 'SDK Manager'. Or in setting, click 'Appearance & Behavior'->'System Setting'->'Android SDK'.

Click 'Edit' besides 'Android SDK Location'. Set your Android SDK Location to 'C:\Users\???\AppData\Local\Android\Sdk' (replace ??? with your account).

Make sure you have internet connection, or you have set proper proxy if you stays in some intranet. Then, android studio will detect that you have not installed SDK and SDK platform. Check them and click 'Next'.