Since there is no downgrade path from Windows XP Pro to Windows XP
Home, you can't.
You need to back-up all important data and perform a Clean
Installation.
Clean Installation
Disconnect all peripherals (camera, printer, scanner, etc)
Disconnect network/modem cable.
Go to BIOS and set CDROM as boot device before hard drive.
Insert Windows XP CD and reboot.
At "Press any key to boot to CDROM" quickly press a key and follow the
prompts for a Clean installation:
http://www.winsupersite.com/showcase/windowsxp_sg_clean.asp
If you are installing using Windows XP Upgrade, insert qualifying
media in Step 4b.
Delete all partitions in step 5 if you desire to erase all data on the
hard drive.
Partitioning and formatting will be done automatically.
All data will be destroyed, back-up important data first.
Enable or install firewall BEFORE connecting network cable.
http://support.microsoft.com/?kbid=283673
Install ALL Critical Windows Updates:
Start/All Programs/Windows Update
After you are finished, you will need to load the appropriate drivers.
If your computer was shipped with Windows XP, these procedures may or
may not apply.
Check your manual or contact the computer manufacturer for more
details.
