What were the key drivers of Microsoft's massive success in the 90s?

Microsoft enabled and capitalized on the massive growth of the PC in the’s.  Microsoft provided a standard software platform, which brought life to powerful, inexpensive hardware from hundreds of vendors all over the world.  The sun never set on the PC empire.  Microsoft drove and benefited from the transition from DOS based PC to graphical UI’s – with Windows and with the best graphical apps (Word, Excel, etc.).   That inflection point was Microsoft's key opening. 

 It drove the virtuous cycle of an easy to use, consumer oriented OS (Windows3.x and) led to millions of users, which led to more applications which led to more PC manufacturers shipping more computers with Windows which led to more users, and so on.  It then broadened its business from desktops and individual users to enterprises and IT, complementing the consumer oriented Windows3.x/ with Windows NT, NT Server, and the enterprise server apps like Exchange and Active Directory.

One of the unsung heroes of Microsoft’s success in establishing Windows is the role Visual Basic played.  As companies were making the transition to graphical computing, VB made it so companies with modest app development abilities could easily develop many of their standard form based applications, like order entry.  Today of course people use HTML but back then VB did incredible missionary work for Windows.  Windows had the apps and the dev tools, which were a major reason for its winning in the market.

In the’s the company had a view that it did whatever it could to make its customers successful, and its own success would be a byproduct of its customers’ success.  By customers, I mean end users; IT managers who deployed and supported Windows; companies that developed apps for Windows, both those for sale to third parties and for their own internal use; hardware manufacturers that developed Windows PCs and devices; service organizations that would devise solutions based on Windows and Office; and so on.

Once you get that virtuous cycle going, it’s a beautiful thing.

Basm allah alrahman alrahim

I think any success need a very good team and a good leader , observe the team first

agree with the answer to Mr.  Mohammed Ashraf 

Thanks for the invitation. I agree with your answer-----------------------------------------------------

Thanks for invitation

I am agree with your answer my colleague’s Mr Mohammed Ashraf you gives us good answers

Thanks for the invitation

Agree with your answer

full agree with ur answer sir

Thanks for the invite. I agree with Mr. Ashraf's answer. 

I agree with your answer , thanks for invitation.

I apologize this is not my specialist

Microsoft was founded in 1975. The key drivers of its  success are

Successful transition from low-margin software provider for low-margin hardware business

Successful introduction of enterprise software and upgrades, OFFICE suite

Successful introduction of enterprise operating systems and software, WinNT and Win2k

Successful introduction of consumer and enterprise operating systems, Win95, Win98, Win2k, WinXP

Integration of Internet Explorer within Win98 and a consent degree with DOJ and European regulators not to break up the company

Successful deployment of enterprise productivity to consumers

Successful purchase and integration of smaller software companies into its enterprise product lines

Successful purchase, development, and deployment of consumer software such as Encarta and Quicken

Partnerships with varying degrees of success to become a content provider for the Internet and cable-TV

Smooth top leadership changes

Settlement of Antitrust charges without breaking up the company

Aggressive use of licensing agreements to leverage its core intellectual properties

Chronology 

In 1989 the company introduced Microsoft Office, a "suite" of programs that eventually came to dominate the market and become Microsoft's best-selling application program...

Before 1990 Microsoft was primarily a supplier to hardware manufacturers, but after 1990 the bulk of the company's revenues came from sales to consumers. That year Microsoft became the first software company to reach $1 billion in revenues, closing the year with 5,600 employees.

1990: Jon Shirley retires as president and CEO; Michael R. Hallman is promoted in Shirley's place; the company becomes the first PC software firm to surpass $1 billion of sales in a single year.

1993: The company introduces Windows NT.

1995: The company introduces Windows95

1997: The Justice Department alleges that Microsoft violated a 1994 consent decree concerning licensing the Windows operating system to computer manufacturers.

1998: The U.S. Department of Justice files two antitrust cases against Microsoft, alleging the company had violated the Sherman Act.

2001: Microsoft Windows XP is released internationally.

2002 Microsoft settles with DOJ

2003: Microsoft launches Windows Server 2003.