Open ScreenRulerSetup.exe and install the software.
Activate trial version of ScrenRuler
Starting ScreenRuler for the first time, you will see the activation screen. Clicking on "Activate" will allow you to use ScreenRuler for 30 days as a fully working trial software. This screen will only appear once. If you are satisfied using ScreenRuler, you can buy it by ordering a license key.