How to install Windows XP Professional on a previous OS

If there's a system already installed on your PC or your computer does not support booting from a CD-ROM, you can install Windows XP Professional from a CDROM without having to boot from the Windows XP Professional installation CD-ROM.

1. If there is an operating system currently installed on your computer, start the computer, log on as an administrator or a user with administrative privileges, and insert the Windows XP Professional CDROM into the CD-ROM drive.
2. When the Welcome To Microsoft Windows XP page pops up, click Install Windows XP.
3. If you see a Windows Setup message box indicating that the version of the operating system cannot be upgraded and that option to upgrade will not be available, click OK.
4. On the Welcome To Setup page in the Installation Type box, click New Installation (Advanced), click Next.
5. On the License Agreement page, read the license agreement, select I Accept This Agreement, click Next.
6. On the Your Product Key page, type in your 25-character product key, click Next.
7. The Setup Options page allows you to configure the following three options:
   - Advanced Options Allows you to control where the installation files are obtained, where the installation files are copied to, whether or not to copy all installation files to the hard disk, and whether or not you want to specify the drive letter and partition during Setup.
   - Accessibility Options Gives you the option of using the Microsoft Magnifier during Setup to display an enlarged portion of the screen in a separate window for users with limited vision and the option of using the Microsoft Narrator to read the contents of the screen for users who are blind.
   - Select The Primary Language And Region You Want To Use - to specify your language and region.
8. After configuration, click Next.
9. Setup displays the Get Updated Setup Files dialog box. If your PC has access to the Internet,select the Yes, Download The Updated Setup Files (Recommended) check box, and click Next. Otherwise, select No, Skip This Step And Continue Installing Windows, and then
   click Next.
10. If your disk partition is not currently formatted with NTFS, the Setup Wizard displays the Upgrade To The Windows NTFS File System page. If you get the Upgrade To The Windows NTFS File System page, ensure that Yes, Upgrade My Drive is selected, and then click Next.
11. If you are installing a Windows XP Professional Evaluation Edition , the Setup Wizard displays the Setup Notification page, informing you that this is an evaluation version. If Setup displays the Setup Notification screen, press ENTER to continue.
12. On the Welcome To Setup page, press ENTER to install Windows XP Professional.
13. The Setup Wizard prompts you to select an area of free space on an existing partition to install Windows XP Professional. Select the C partition. The Setup Wizard displays the following message: You Chose To Install Windows XP On A Partition That Contains Another Operating System. Installing Windows XP Professional On This Partition Might Cause The Other Operating System To Function Improperly.
14. Press C to continue Setup.
15. If you get an information that a Windows folder already exists, press L to use the folder and delete the installation in it. If your partition was not previously formatted with NTFS and you choose to have the partition formatted as NTFS, Setup formats it, and then copies files. Otherwise, Setup examines the partition and then copies files.
16. The Setup Wizard reboots the PC and continues to copy files in a graphic (GUI) mode, then it displays the Regional And Language Options page. Choose the appropriate system locale, user locale, and keyboard layout and click Next.
17. Setup shows the Personalize Your Software page, asking you for your name and your organization name. The Setup Wizard uses your organization name to generate the default computer name. If you install applications later they may use this information for document identification and registration. Fill the boxed appropriately and then click Next.
18. The Setup Wizard displays the Computer Name And Administrator Password page. Type a name for the computer in the Computer Name text box. If your PC is connected to LAN, ask your administartor for a name of your PC.
19. In the Administrator Password text box and in the Confirm Password text box, type a password, click Next. You may leave the box empty.
20. Depending on your computer configuration, the Setup Wizard might display the Modem Dialing Information page. You need to give following information:
    - The correct country or region is selected.
    - Type the correct area code or city code.
    - If you dial a number to get an outside line, type the number.
    - Ensure that the correct dialing tone is selected, and click Next.
21. The Setup Wizard displays the Date And Time Settings page. If necessary, select the time zone for your location from the Time Zone drop-down list, and adjust the date and the time. Ensure that the Automatically Adjust Clock For Daylight Saving Changes check box is selected if you want Windows XP Professional to automatically adjust the time on your computer for daylight savings time, and then click Next.
22. Check that Typical Settings is selected and click Next.
23. On the Workgroup Or Computer Domain page, ensure that the No, This Computer Is Not On A Network, Or Is On A Network Without A Domain option is selected, make sure that the workgroup name is Workgroup, and then click Next.
24. The Setup Wizard configures the networking components and then copies files, installs Start menu items, registers components, saves settings, and removes temporary files. This process takes several minutes.
25. The PC restarts, and Windows XP Professional starts for the first time.