Windows was always designed to make the life easy for end users by offering cutting edge GUI.....

It was meant to even let a lame user use the PC and conduct common activities with almost no configuration.... Anything goes wrong CTRl -ALT - DEL and you are back to your work... Even if machine restarts on its own.. no problems majority of time.. Windows will boot after running the Scandisk (most of the time)


Other OS are never so user friendly... They had lot of configuration to be made..... and in short needed some level of expertise to use the system.. offlate there are good GUI for Linux..

Again MS binds with almost all the majproty of hardware available today... I have known how long it takes to set the printer on linux.... especially if u are using a custom printer... It had actually taken us 2 weeks to search for a driver..... All this implies that MS products comes with lot of per-configuration.. which surely shall live some doors opens.....

Imagine.. A situation u are developing a stadium....

Now for ease if you create say 100 entry doors.... all this doors also become a source of vulnerability.... I guess u have to apply the law of demand and supply .... How much of comfort do I desire and how much of compromise Am it willing to do.....

Nihil rightly mentioned... It is a volume business.... MS is undoubtedly the most popular OS atleast on the Desktop front.....

MS is undisputed leader in Office Automation ......

MS is a major player in Email programs

MS is a leader for Internet Browsers....

Incidentally it also ends up being a target of many hackers........