How to downgrade from Windows Vista to Windows XP using Windows XP installation CD?
WARNING: There is a risk of data loss. All data, files and programs on the C:\ partition of the hard drive will be lost. Backup any data before proceeding.
* A USB floppy drive is required to complete this procedure.
* Before starting this procedure, download all the Windows XP operating system drivers for your model from the Download section in Sony Asia Site.
1. Download the SATA Driver for Microsoft Windows XP Operating System update available at the Downloads section of the Sony Support website.
2. Insert a USB floppy disk drive to the computer and insert a blank floppy disk.
3. Save the files to A:\.
4. Remove the floppy disk
5. Verify the computer is configured to boot from CD in the BIOS.
6. Insert a Windows XP operating system installation CD into the optical disk drive.
7. Restart the computer.
8. When the Press any key to boot from CD message appears, press any key on the keyboard.
9. When the Press F6 if you need to install a third party SCSI or RAID or driver message appears on the screen, press the F6 key.
10. Insert back the floppy disk into the USB floppy drive.
11. At the Windows Setup could not determine the type of one or more mass storage devices screen, press the S key.
NOTE: A list of SATA drivers is displayed.
12. Select Intel ICH9M in the list and then press the ENTER key.
13. Press the Enter key to continue with setup.
14. At the Windows XP Professional Setup screen, press the ENTER key.
15. Press the F8 key to accept the Windows XP license agreement.
16. At the following list shows the existing partitions and unpartitioned space on this computer screen, select the C: partition and press the ENTER key.
17. Select Format the partition using the NTFS file system (Quick) and press the ENTER key.
WARNING: There is a risk of data loss. All data will be removed from the C:\ partition on the hard drive.
18. Press the F key to confirm formatting the drive.
19. Follow onscreen prompts to complete installation of the Windows XP operating system.
NOTE: After the installation is complete, the Windows desktop is displayed.
20. You need to install drivers and applications to complete the setup.