Bill Gates and Paul Allen formed Microsoft in 1975 to focus on developing the MS-DOS operating system. Over time, Microsoft introduced graphical user interface operating systems like Windows to make computers easier to use. Key versions included Windows 95 which introduced the Start menu and taskbar, and Windows 10 which unified the desktop and mobile interfaces and introduced features like Cortana and Continuum Mode. Windows has evolved from a command-line interface to one optimized for touchscreens, with Microsoft aiming to deliver a consistent experience across all device types.

1.  Earlier days DOS disk operating system refined by BILL GATES and PAUL
ALLEN in the 1970's
 In 1975,BILL GATES and PAUL ALLEN form a partnership called MICROSOFT.
 Microsoft focuses on a new operating system-the software that manages, or runs,
the computer hardware and also serves to bridge the gap between the computer
hardware and programs, such as a word processor. They name their new
operating system "MS-DOS".
 Rather than typing MS-DOS commands, you just move a mouse to point and
click your way through screens, or “windows.
 There are drop-down menus, scroll bars, icons, and dialog boxes that make
programs easier to learn and use.
 You're able to switch among several programs without having to quit and restart
each one. Windows 1.0 ships with several programs, including MS-DOS file
management, Paint, Windows Writer, Notepad, Calculator, and a calendar, card
file, and clock.

2.  The first versions of Windows (1.0 through to 3.11) were actually just programs run from MS-
DOS which then took over the screen and launched an application called Program Manager.
 Later on, Windows 95, introduced many staple features that remain in current versions of
Windows today, including the Start menu, the taskbar, and Windows Explorer.
 In 1997, Microsoft released Internet Explorer 4 which included the (at the time) controversial
Windows Desktop Update, which aimed to integrate Internet Explorer and the web into the
user interface and also brought many new features into Windows, such as the ability to
display JPEG images as the desktop wallpaper and single window navigation in Windows
Explorer.
 Windows 98, which also included the Windows Desktop Update and Internet Explorer 4
by default. It also included plug and play, which allowed devices to simply work when
plugged in instead of requiring a system reboot, and USB support out of the box.
 Windows 2000 (codenamed NT 5.0), many consumer-oriented features from Windows 95 and
Windows 98 were included, such as the Windows Desktop Update, Internet Explorer 5, USB
support and Windows Media Player.
 Windows XP, which introduced a new theme called Luna, a more user-friendly interface,
updated versions of Windows Media Player and Internet Explorer, and extended features
from Windows such as the Help and Support Center and System Restore.
 Windows Vista focused on securing the Windows operating system against computer viruses
and other malicious software.
 Windows 7 also removed many extra features, such as Windows Movie Maker, Windows
Photo Gallery and Windows Mail, instead requiring users download a separate Windows
Live Essentials to gain those features and other online services.

3.  Windows 7 is released for the wireless world . It's become common to connect to
public wireless hotspots and private networks.
 The debut of Windows Touch, which lets touchscreen users browse the web, flip
through photos, and open files and folders.
 When you log in to Windows 8, the first screen you see is the new ‘Start Screen’, also
known as ‘Metro’.
 Instead of Icons, the new Start screen has ‘Tiles’. You click these to open your ‘Apps’
(short for Applications). If you can’t find a particular tile, do a right mouse click in
the space at the bottom of the screen and click All Apps.
 Windows 8 comes with an antivirus program called ‘Defender’.
 Whereas in Windows 7 you might have used Windows Live Mail for your email,
Windows 8 has a new ‘Mail’app.
 Instead of having separate contacts for email, Skype and social networking e.g.
Facebook, you will find all your contacts together in the new 'People' app.

4.  If we are on the Windows 8 Start screen with the tiles and I move my mouse or
finger to the upper right corner of the screen, the soon-to-be-famous Windows 8
“charms” come out.
 In Windows 10, Microsoft has finally brought back the desktop Start menu, and it’s
glorious.
 Having a single user interface that spans desktops, laptops, tablets and
smartphones sounds like a terrible idea. Microsoft did it anyway with Windows 8,
but fixed the problem in Windows 10.
 Now, we have Continuum Mode, which alters Windows 10’s user interface based on
whether you’re on a tablet or a PC. And if you have a hybrid device, you can even
switch back and forth depending on whether you’re in laptop mode or tablet mode.
 Cortana is clever new personal assistant, and she can search the web, find things
on your PC, keep track of your calendar—even tell you jokes.
 Task View (virtual desktops)- If you open a lot of programs at once, this feature
allows you to keep them organized.
Windows 10 will be able to run on all devices from phones to servers and there will
be a single app store across the lot. All older Windows Store apps will work with
Windows 10.
Sparatan – A new web browser rather than Internet Explorer, which allows users to
annotate webpages or save them to read later.
A feature known as Task View displays all open windows and allows users to switch
between them, or switch between multiple workspaces.