It does take a bit of doing but here are the steps in more accurate detail.
1> Copy all the xp home(OEM or Upgrade) files off the disc to a local drive.
(to get xp sp2 (download me here) slipstreamed into the oem folder I simply used a program called Nlite More about this program later.)

2> Next I opened the "I386" folder looked for "winnt.sif" and edited it.
Here is how I run automated installs using this file.

[Data]
Autopartition = 0
MsDosInitiated = 0
UnattendedInstall = Yes
[Unattended]
UnattendMode = FullUnattended
UnattendSwitch = No
OemPreinstall = Yes
OemSkipEula = Yes
FileSystem = *
WaitForReboot = No
NoWaitAfterTextMode = 1
NoWaitAfterGUIMode = 1
TargetPath = Windows
ProgramFilesDir = "C:\Program Files"
CommonProgramFilesDir = "C:\Program Files\Common"
DriverSigningPolicy = Ignore
NonDriverSigningPolicy = Ignore
[Display] Xresolution = 1024
Yresolution = 768
BitsPerPel = 32
Vrefresh = 75
[GuiUnattended]
EncryptedAdminPassword = No
AdminPassword = "Whatever You Want"
TimeZone = 010
OEMSkipRegional = 1
OemSkipWelcome = 1

[Shell]
DefaultThemesOff = Yes
DefaultStartPanelOff = Yes

[LicenseFilePrintData]
AutoMode = PerServer
AutoUsers = 20

[Components]
iis_common = On
iis_inetmgr = On
iis_pwmgr = Off
iis_doc = Off
iis_www = On
Iis_www_vdir_printers = Off
Iis_www_vdir_scripts = Off

[UserData]
ProductKey = "*****-*****-*****-*****-*****" ---THis will enable you to install without putting your product key in!
ComputerName = RENAME_ME
FullName = "Your FUllName"
OrgName = "Your OrgName"

[RegionalSettings]
Language = 0409

[Networking]
InstallDefaultComponents = Yes

[Identification]
JoinWorkgroup = workgroup
Here is the file if you want to just edit it yourself. (open in notepad only) winnt.sif .


You can also use Nlite to automate this also.


4>Then I edited the "setupreg.hiv" This was the most tricky part. To do this you need to open up regedit and go to
"HKEY_LOCAL_MACHINE" Highlight it and click on file and load hive.
Load "i386\Setupreg.hiv". regedit will ask for a name
name it "Homekey".
Drill down throught this key untill you find "HKEY_LOCAL_MACHINE\Homekey\ControlSet001\Services\setupdd"
all you have to do is edit the binary key "default" and change all "01" and "02" to "00".
Once you have done this you can save it and go back and highlight "Homekey" entry and go to file and "unload hive"
it should ask to where and save it to "i386\Setupreg.hiv". It will ask you to overwrite the existing. Go ahead and do so.

If you do not feel comfortable with doing this yourself you can down load my Setupreg.hiv.

5>Now run Nlite to slipstream xp sp2 into the "I386" folder
Nlite will also allow you to tweak your install and delete unnessasary language files as well as help files.
Nlite will ask you to create an ISO of your new install wherever you would like it to go.

****With Nlite you can also disable activation!!!*** VERY KEY feature....
Here is the WPA.DB_ that will kill activation. (right click and choose "save as")

A great thing about Nlite is it will also include the much needed boot img and files you need to do the oem install

Thats it.

You now have a fully usable windows xp pro lite.

a drawback that I have found!
The Usermanagement software found in pro is not included.(I am looking for a way to hack this).
View: Turn XP Home into XP Pro Lite


Or a much simpler method:
You need to copy the root directory and the i386 directory of the WindowsXP CD to your harddisk, extract the Bootsector of your WindowsXP CD and change only 2 bytes in i386\Setupreg.hiv by using Regedit. In fact all you have to do is edit the binary key "default" and change "01" to "00" and "02" to "00" in HKEY_LOCAL_MACHINE\Homekey\ControlSet001\Services\setupdd, C'T claims.

There is one big drawback, though. Users won't be able to install Service Pack 2, unless they integrate SP2 in the installation CD. And that's probably too much trouble for most users, who of course are better off buying a legal version anyway. It is expected that Microsoft will change the setup files soon to prevent this hack.

Theregister (http://www.theregister.co.uk/2005/06/03/xp_hack/)