Soliodworks can not be installed

Hello,
I have the problem that I can no longer start respectively reinstall Solidworks. After reinstalling the 3DExperience Launcher, I can no longer start even that, the port number is also not recognized. I would like to ask support for help, but I have to log in with my serial number, which I do not have access to because SW has already been uninstalled. Can anyone help me here?