VGS is commercial software. It's not sold anymore (nor is it supported or updated) so you're going to have to find it yourself. There's a demo available but it has limited functionality. Try a search engine like www.google.ca
"The term of copyright. Rights in works for hire span 120 years from the date of creation or 95 years from the date of publication, whichever is shorter. The term for other works (at least when the author or artist is identifiable) extends for the artist's lifetime and 70 years beyond. Indeed, in the case of joint works, copyright lasts 70 years beyond death of the last surviving author. More information."
"Rights in a work not for hire revert back to its creator (or the family of those who are deceased) after approximately 35 years even if copyright has been unconditionally sold or licensed to others."
So, for any software produced on 1980 and later, the copyright is retained by the author (or the hirer) at least until 2050 (in the optimistic case that the author died also on 1980). However...
Taken from http://www.officialsoftware.com/portal/account-resources-c-intro.asp
"The United States has copyright relations with more than 100 countries throughout the world, and as a result of these agreements, we honor each other's citizens' copyrights. However, the United States does not have such copyright relationships with every country. For a listing of countries and the nature of their copyright relations with the United States, request Circular 38a, "International Copyright Relations of the United States."
So, in certain countries (like Kiribati, Democratic People’s Republic of Korea, Iraq, Iran, Ethiopia, Comoros, Afghanistan, Bhutan, Jordan, Nepal, Nauru, Palau, Oman, Sudan, Tuvalu, São Tomé and Principe, Seychelles, San Marino, Seychelles, Tonga, Vanuatu, Somalia, Syria, Yemen and Western Samoa) may be legal(?) or at least questionable the piracy of a work with copyright registered on USA.