- Click the Start button.
- Right Click on Computer (or My Computer) and select Properties.
- On the left, click on “Advanced system settings” (Windows XP users can ignore this step).
- Click the “Advanced” tab.
- Click on “Environment Variables” button near the bottom.
- Click “New” and enter a “Variable name:” and “Variable value” and click OK.
- Click OK and click OK again to get out of System Properties and save your changes.
To use your new variable enter a % character before and after.
For example: testenv would be %testenv%
For example: testenv would be %testenv%