If CR3 M080 is still working then you can go to CREO3_LOADPOINT\Creo 3.0\M070\Parametric\bin directory and open parametric.psf file in Notepad. Then you can locate 2 important lines:
When you install any other Creo version you have to enter 7788@servername as license source. If you do this then installation procedure will create parametric.psf file automatically. If you own several license types then you have to customize launch command creation during installation.