This can happen following a major Windows update.
The WebEasy serial number is actually still valid.
Please uninstall the program, and then delete the program folder C:\Program Files\Avanquest\Web Easy Professional 9
The new install will not disturb your existing projects. They are stored apart from the program, in your Documents\Web Easy\ path.
Please download the installer for WebEasy 9 from this link:
Be sure to SAVE the file, don’t try to run the install straight from the link.
Then run the downloaded file WE18.104.22.168-Pro-ENU.exe to reinstall WebEasy 9. However, when it finishes installation do not run WebEasy yet.
Go to the program folder C:\Program Files\Avanquest\Web Easy Professional 9
Right click on Webeasy.exe and go to Properties.
Go to the Compatibility tab and verify that compatibility mode is NOT enabled.
Make sure that "run as administrator" is also not checked.
If you have BitDefender, or Trend Micro software, you will need to create an exception for WebEasy to allow it to run.
Click on the Settings icon on the top right of the program.
On the list of items on the left, select Antivirus.
Click on the Exclusions tab at the top.
Click on the Excluded Processes link/button.
Click the Add button.
Click Browse and locate the WebEasy executable file and select it. This is located in C:\Program Files\Avanquest\Web Easy Professional 9\webeasy.exe
Then try to run the program.