I'm pretty sure the hint is on your screenshot:
"M2_HOME is used by default".
Check your System paths:
- Select Computer from the Start menu
- Choose System Properties from the context menu
- Click Advanced system settings > Advanced tab
- Click on Environment Variables
- Under System Variables, find PATH, and click on it.
- Click on the Edit button, find the M2_HOME entry and change the path to the directory you want it to be.