Both Strawberry and ActiveState behave pretty well according to Win32 path and install standards. Whether the previous admin of this box kept to those standards, might be another story. Managing environment variables on Windows Server 2012 is more of a Windows Server admin question than a Perl question. That being said, it's pretty easy: Control Panel > System and Security > System > Advanced System Settings, and then look for the Environment Variables button (might be in a different tab), or ask your network admin for assistance.