BigLebowski

Hello, I have a Windows10 laptop and Cura just ran fine until a few days ago. Since then Cura 4.0.0 won´t start anymore. I already reinstalled, rebooted etc. several times. When I click on Cura it looks like it´s starting but the GUI doesn´t come up. I can see the Cura process in the Task Manager, but no GUI. Anybody else having that problem? Any solutions? Herbert