Slight modification of the method and no dual os.

My friend brought me a toshiba laptop to fix but it did not have dock with it so we had no DVDROM or floopy.
I installed XP on the laptop using method which is similar to yours but with a few steps which are different to removing Dual OS before the setup.

Here is what I did to get XP on it.
Required items:
98SE bootdisk
40-Pin to 44-pin 2.5 adaptor to connect HDD to working computer.

1) Connect Laptop HDD to desktop working system using the convertor. Format the HDD and create 2 partition. Recommend using FAT32 for both. Second partition does not need to big but will be used to store windows install files.
(for my friend 's 60GB HDD we did 30GB and 25GB partition)

2) Copy 98SE bootdisk files included hidden ones to primary partition. We also using XP 's disk manger and set this partition to be active.
Here is list of files incase you wonder which ones: command.com config.sys drvspace.bin Himem.sys IO.sys ramdrive.sys msdos.sys should be more than enough. Rest can be ignored. You can also edit the config.sys with notepad and remove all entry except keeping the following
[COMMON]
device=himem.sys /testmem:off
devicehigh=ramdrive.sys /E 2048

3) Copy smartdrv.exe, format.com (usually located in EBD.cab) to second smaller partition.

4) Copy the i386 folder of a XP CD to second partition. Also copy any apps, driver you may need for your laptop.
Note: I also added a winnt.sif file to the i386 directory and added unattended install information along with XP CD key to make it so that I don't have to sit during the install process.

5) Using a working desktop: Unplug any and all HDD from a system. plug only the Laptop HDD. insert the 98SE bootdisk into the floopy drive on the system.
Choose boot with CD-ROM support.
At the A: prompt type C: and verify all the bootfiles you copied earlier are there.
type A: to get back to A prompt.
type sys C:
Once system is copied. shutdown the box and remove the laptop hdd.

6) Plug laptop HDD back into laptop. Bootup and you will see C: prompt.
Type D: to access to second partition.
Type smartdrv
to make the process of copying faster.
Type format /Q C:
to format the C: drive and clean up the 98se stuff off it.
Type CD i386 to switch to windows files folder with all setup files.
Use the winnt.exe to start the setup.

For my friend I did
winnt /s:D:\i386 /u:winnt.sif /t:C:
/s is source where all setup files are.
/u:winnt.sif is the unattended command file
/t:C: is switch to tell setup to copy files to C: drive and install XP to C: drive.

XP setup should now copy files and you will not have deal with any DOS installation or dual OS issues. You can also convert to NTFS during the setup without any issue.

For those you don't use winnt.sif for unattended install. Here is small tip to help you pass some time during install.

Once you are 30min remaining into the install, you can start playing games like freecell or solitare to pass the time during the install.
Steps to running games during install
During XP setup do Shift+F10
You will get dos prompt
Type start freecell OR start sol OR start pinball
or use paint to do some drawing if you like.
Pinball is not ready until you have 13min remaining in setup.

Once you are XP install is done you can delete the files of the second partition if you like or keep em there for future.


mWMA
Have a nice day.