Difference Between Windows 2000 and Xp

XP Professional and XP Home Edition share the same kernel (the "guts" of the operating system), and this kernel is based on the Windows 2000 operating system. The differences between them are in the level of security they provide, networking capabilities, and advanced features. For business users, Windows XP Professional is very similar to Windows 2000 in its feature set. XP Professional supports multiple processors, multiple monitors (up to 9), Group Policy. Encrypting File System, Dynamic Disks, IIS, a built in backup program, and advanced networking capabilities (such as IPSec.) All of these features are missing from XP Home Edition. Another important distinction between the two versions is that XP Home Edition cannot join a Windows NT/2000/2003 domain. If you wish to network with other PC's in your home or office, you must be part of a workgroup. If you're a "power user" purchasing Windows XP for your personal workstation, Windows XP Professional is a better choice than Home Edition, if you can afford the price difference. Windows XP Professional is also more secure than Home Edition, which is an important consideration for users with a full time high speed internet connection.
What are the differences between Windows 2000 Professional and Windows XP Professional?
Not much. Microsoft has added a host of new features to both versions of Windows XP, but nothing that appears to be absolutely compelling for business users. One of the new features called "Fast User Switching" allows to to run two separate logged in sessions at once. This allows a user to do everyday work such as e-mail using a non-privileged user account, and then run an Administrative session at the same time without rebooting or resorting to the "Run As" command. This also allows you to quickly log onto any users workstation and make administrative changes without logging them off. The remote assistance feature of XP can also help reduce support costs by allowing your Help Desk staff to interact with a user's PC over the network. XP's built in ZIP compression support can also save your company a lot of money in licensing fees if you are currently using a third party utility such as WinZIP.

The official Microsoft answer is that XP stands for "experience", in the sense that they are combining their years of experience creating two very successful desktop operating systems into one really great product. Pundits have come up with their own definitions of XP, including "eXPensive" and "eXtra Profits"

It seems that Microsoft has always configured its Operating Systems for the future generation of hardware, and XP is no exception. Unless you bought a PC recently, you'll probably want to upgrade your desktop PC before you upgrade your OS. Below is a table of bare minimum and recommended hardware requirements, as well as our "real word" recommendations.
Windows XP system requirements
Componen Bare Minimum Recommended "Real World"
CPU 233 Mhz 300 Mhz +600 Mhz
Memory 64Mb 128Mb +256Mb
Free Disk Space 1.5GB 2.0GB +8GB