Thank you, I'm gonna try the Cleanup Script.
But does it clean all Adobe softwares (photoshop, illustrator,…) ?
Can we choose to clean only Premiere ?
EDIT: I tried the Cleanup and reinstall but it says again that it cannot load the trial period.
Has a demo ever been installed before? You can only do it once.
Only one install.
Is there a file I can remove to clean all trace of Premiere?
My guess would be a hidden registry entry that even CleanScript doesn't touch. Otherwise you could just forever reinstall the trial and never have to buy.