BSD, Lunix, Debian and Mandrake are all versions of an illegal hacker operation system, invented by a Soviet computer hacker named Linyos Torovoltos, before the Russians lost the Cold War. It is based on a program called "xenix", which was written by Microsoft for the US government. These programs are used by hackers to break into other people's computer systems to steal credit card numbers. They may also be used to break into people's stereos to steal their music, using the "mp3" program. Torovoltos is a notorious hacker, responsible for writing many hacker programs, such as "telnet", which is used by hackers to connect to machines on the internet without using a telephone.
Your son may try to install "lunix" on your hard drive. If he is careful, you may not notice its presence, however, lunix is a capricious beast, and if handled incorrectly, your son may damage your computer, and even break it completely by deleting Windows, at which point you will have to have your computer repaired by a professional.
If you see the word "LILO" during your windows startup (just after you turn the machine on), your son has installed lunix. In order to get rid of it, you will have to send your computer back to the manufacturer, and have them fit a new hard drive. Lunix is extremely dangerous software, and cannot be removed without destroying part of your hard disk surface.