If your new computer has a CD/DVD drive (though few new computers have one these days), just put the installation disk in the drive and install SMSP12 from the disk. If your new computer doesn't have a CD/DVD drive, then copy the installation disk on to a memory stick or external HDD from your old computer (which presumably has a built-in CD/DVD drive) and install SMSP12 from the copy - assuming that the original installation disk isn't copy protected. Or go to your MAGIX My Account and download the .exe file from the SMSP12 listing under My Products (Sony registration data should - but not in all cases - have been transferred to MAGIX with the change in ownership of the Vegas line of products in 2016). Or go to point 6 in https://www.vegascreativesoftware.info/us/forum/faq-where-can-i-download-vegas-movie-studio-17-or-earlier--134340/ and search the listed links to find your version of SMSP12 and download the program from there (NB: the legacy links are not official Sony/MAGIX websites so its caveat emptor using any of the DLs in the links).