Win 9x, WinNT, Win2000

What's the basic difference between Win9x, WinNT and Win2000?

Moreover, if I install an edition of Win2000 over the previous one (e.g. Server over Professional, OR Professional over adv. server), will the new edition install correctly?

So what are the differences betweem the different versions of Windows?

Thanking in advance for answering the questions.

Saeed Mazhar.
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Lee W, MVPTechnology and Business Process AdvisorCommented:
BASIC Differences:
Windows 9x is a hybrid of Windows 3.1, DOS, and Windows NT.  It still has and utilizes 16bit code (especially in video performance).  It allows direct access to hardware for all programs without necessarily going through the system first.  This is one of the reasons for its instabilities.  Windows 9x is also "plug-and-play" which generally means, that if all is right with the universe, if you install another peice of hardware in the computer (or otherwise connect it to the computer) Windows will "see" it the next time it's booted and, at worst, ask you for a driver disk (Plug-and-play generally meaning that you open the box, take the new hardware and just "plug-it-in" and windows and your computer do the rest - used to be that you needed to set "jumpers" - little switches - so the hardware would work properly, and if you didn't set things right, you had problems).

Windows NT 4 is a TRUE 32 bit operating system.  It contains a limited (but fairly extensive) support for 16 bit programs.  In other words, MOST (but not all) 16 bit programs will work on Windows NT - this includes MOST, but not all, Windows 3.1 programs and DOS programs (DOS programs which aren't graphics intensive and don't directly attempt to access hardware like old DOS games or specialized scientific programs, for example).  Windows NT does NOT utilize DOS, though it has many of the same commands - there is no "boot to DOS" option.  Further, NT is FAR more secure than 9x.  Depending on how you configure it, you can have per file file permissions so if you are not logged on as the correct person, you cannot access the file.  Windows NT 4 (and earlier) are NOT plug-and-play - so configuring certain new hardware can be difficult.  It's not meant for the average home user.  It also lacks support for some newer technologies - such as USB.

Windows 2000 was to be Windows NT 5.0.  It's more like Windows 9x in that it is now a "plug-and-play" operating system.  But it still retains most of the aspects of Windows NT 4.0.  The major differences come in how it's networked and such.  

A further note - Windows NT/2000 supports multiple CPUs - so if you have a dual processor motherboard, you can utilize both CPUs.  If you had a dual CPU system and ran Win9x, you would never use the second CPU.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Lee W, MVPTechnology and Business Process AdvisorCommented:
Further information:

If you have windows 9x installed, Winnt will NOT upgrade it - it will recognize that it's there and make the system a dual boot (provided you don't convert the drive to NTFS from FAT.  (also, NT 4 does not support FAT32 and cannot be easily installed on a FAT 32 system).

Windows 2000 will upgrade a Win9x system.

You cannot upgrade from NT 4 Workstation to Win2K server, only to Win2K professional (workstation).
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Windows 2000

From novice to tech pro — start learning today.