Trial version expired after three days?

 From:  Antlab
I read several good references to MOI, and so I downloaded the trial version to test it, before purchasing. The problem is that now, after only three (3) days, when I start the program a message window says that the trial period has expired. I am very interested in MOI, and I plan to buy it, but I would like to know why the trial version on my PC doesn't work after a so short period. I don't know if this can help, but I use Vista Business, and usually I don't have problems running graphic software (Blender, ZBrush, PS, Painter and so on).

Best regards