I hesitate to just toss up suggestions on securing your tech without knowing what you are running. Poll Definitions: WinNT - NT3, NT5, 2000, 2003, XP, XP SP1, XP SP2: This is the NT "filesystem", introduced with WinNT. This offers "improved stuff" over the preceding VFAT filesystem, including the seperation into Administrative and User access to files. Win9x - Win3.1, Win3.11/WfWG, Win95, Win98, Win98SE, WinME: This is the VFAT filesystem. This filesystem is limited in that it can "only" access disk partitions of less than 2GBs (4?). It does not have the Admin/User seperation that leads to improved management/security of files. Apple - (OS7), OS8, OS9 - The "Classic" Macs; OS X 10.1, 10.2, 10.3, 10.4: I'm not really familiar enough to be sure which OS X is which; I'm pretty sure that 10.4 is Tiger, 10.3 is Panther? There is also a "Cocoa" in there and a "Carbon"? (UNIX has been the underpinings of the R&D community for a long time. It has a philosophy of "small tools that each do one task RIGHT", and can be combined together to form larger applications.) Other - Linux (Linux Is Not UniX) is the effort of a college student that wanted to see if it were possible to build an OS "from scratch". (Linux is not actually a complete "operating system" in and of itself. It is the "heart", or "kernel", of a complete OS.) There are many "distributions" of Linux; efforts by many people to extend the Linux "kernel" into complete "operating systems". Among them are RedHat, SuSE, Mandriva, Slackware, Debian, Gentoo, Ubuntu, and just a laundry list of others. Check out http://ibiblio.org/pub/linux/distributions/ for a listing. Linux distributions – . ibiblio.org *BSD (Berkeley Software Distribution) is the result of efforts at UC-B to extend "AT&T UNIX" to personal computers. (They went through pretty much the same sort of "baptism by fire" that Linux is undergoing with the SCO vs IBM fiaSCO.) Some current "distributions" (usually not called such) include FreeBSD, OpenBSD, NetBSD, DragonFly BSD, TrustedBSD and, I'm sure, there are other flavors. http://www.daemonnews.org/new2bsd/ (See also http://distrowatch.com/ for a bigger picture of the Open Source Operating System offerings.) DistroWatch.com: Put the fun back into computing. Use Linux, BSD. News and feature lists of Linux and BSD distributions. distrowatch.com Amiga - <shrug> There might still be Amiga boxes out there. There are efforts by the tech industry/community to bring AmigaOS back as an "Open Source" project. Other(Other) - "But, wait; there's more!" QNX, Plan9, Ada and some others.