Catia’s bug « click ok to terminate »

Hello everyone

I have just installed catia V5 on my PC but I can’t use it. When I open it the software displays immediately « click ok to terminate », with no other choices. So I click on it and the software shuts down. Everytime I open it the same problem appears. I don’t know what to do to fix it and I have to fix it quickly. What can I do?