Microsoft Windows 7
The first known build of Windows 7 was identified as a “Milestone 1 (M1) code drop” according to TG Daily with a version number of 6.1.6519.1. It was sent to key Microsoft partners by January 2008 in both x86 and x86-64 versions. Though not yet commented on by Microsoft, reviews and screenshots have been published by various sources. The M1 code drop installation comes as either a standalone install or one which requires Windows Vista with Service Pack 1, and creates a dual-boot system. On April 20, 2008, screenshots and videos of a second build of M1 were leaked with a version number of 6.1.6574.1. This build included changes to Windows Explorer as well as a new Windows Health Centre. According to the TG Daily article of January 16, 2008, the Milestone 2 (M2) code drop was at that time scheduled for April or May 2008. A Milestone 2 build was demonstrated at the D6 conference with a build number of 6.1.6589.1.x86fre.winmain_win7m2.080420-1634. The build had a different taskbar than found in Windows Vista, with, among other features, sections divided into different colours. The host declined to comment on it, stating “I’m not supposed to talk about it now today”. According to Paul Thurrott, Milestone 3 (build 6780) was shipped to Microsoft employees and close partners in the week of September 7, 2008. Described as visually and functionally similar to Windows Vista by Mary Jo Foley of ZDNet and Stephen Chapman of UX Evangelist, some bundled applications in Milestone 3 now use a ribbon interface similar to that of Office 2007. Thinknext.net, the same site that was behind the original leaks of Milestone 1 pictures and video, has since leaked 39 images, and 4 videos of Windows 7 build 6780, though Microsoft has since forced them to take the images down. Many applications that had been integrated into previous versions of Windows have been removed, including Calendar, Contacts, Mail, Meeting Space, Movie Maker, and Photo Gallery and are available as downloads in the Windows Live Wave 3 beta release. WinFuture.de has since leaked 192 images of Windows 7 build 6780. On October 28, 2008, Microsoft distributed a pre-beta build of Windows 7 with the build tag 6801.winmain_win7m3.081020-1655 to attendees at its Professional Developers Conference (PDC).  Microsoft also demonstrated build 6933.winmain.081020-1842 during the PDC, but did not give it to attendees. It has a new desktop interface, a new taskbar and many new features. A beta release is planned for early 2009. 6
Mac OS X Snow Leopard
Mac OS X is the newest of Apple Inc.'s Mac OS line of operating systems. Although it is officially designated as simply "version 10" of the Mac OS, "version 9" had a completely different codebase, file system, design, and hardware support. Mac OS had been Apple's primary operating system since 1984, and the family was backward compatible, so Mac OS X supported an emulated version 9 until version 10.5. Unlike its predecessor, Mac OS X is a Unix-like operating system built on technology that had been developed at NeXT through the second half of the 1980s and up until Apple purchased the company in early 1997. It was first released in 1999 as Mac OS X Server 1.0, with a desktop-oriented version (Mac OS X v10.0) following in March 2001. Since then, six more distinct "client" and "server" editions of Mac OS X have been released, the most recent being Mac OS X v10.6, which was first made available on August 28, 2009. Releases of Mac OS X are named after big cats; the current version of Mac OS X is nicknamed "Snow Leopard".
II. SET UP AND INSTALLATION
Microsoft Windows 7
Step 1 - Place Windows 7 DVD in your dvd-rom drive and start your PC. Windows 7 will start to boot up and you will get the following progress bar.
Step 2 - The next screen allows you to setup your language, time and currency format, keyboard or input method. Choose your required settings and click next to continue....