Thanks for the GREAT tutorial. I have successfully reinstalled WinXP on a Panasonic Toughbook, which has only an external CD-ROM and no floppy drive.
I have several suggestions for other readers that might help.
1) When installing the new 2.5" HDD into the desktop computer for formatting, remember to jumper it as a slave . It won't recognize it otherwise, of course, which I realized after multiple frustrating attempts. On my drive, the slave configuration is to vertically jumper the first two pins (of the four jumper pins, the ones farthest from the cable).
2) Know where pin 1 is on your new HDD and line it up correctly with the adapter and the red stripe of the cable. On my HDD, pin 1 is the one closest to the four jumper pins.
3) If you are installing a new HDD larger than 32 GB, you need to create a main partition of 32 GB or smaller. You cannot use FAT32 format if the drive exceeds 32 GB. I formatted an 80 GB drive into three partitions and that worked fine.
4) When installing DOS 7.1 onto the new drive, I tried to install the new HDD as the master, as the instructions indicate. Unfortunately, I never did get the desktop computer to recognize it, even though it was properly formatted and configured as master. I worked around this by installing the /I386 files and smartdrv.exe while the 2.5" drive was installed as the slave. I then rebooted using the DOS 7.1 CD with the new HDD still as slave. When the DOS installation screen came up, it claimed it could not find any FAT drives on my system. It then issued me a stern warning not to continue because it could not install DOS onto a NTFS formatted drive. I clicked "Skip" and continued. At that point I was able to tell it to install onto my second HDD, the new 2.5" FAT32 formatted drive, and that worked well. I allowed it to configure my MBR on that drive. Make sure you indicate the correct drive letter of your 2.5" new drive and not the main drive on your desktop.
5). Make the FAT32 partition "ACTIVE" on the new HDD so the operating system can be found when reinstalled in the laptop. That took several more frustrating re-installation attempts before I discovered that. (I kept getting "No Operating System Found" messages on the laptop). I was able to activate the partition by reinstalling it as the slave in my desktop, then using Control Panel-Administrative Tools-Computer Management-Disk Management. Right click on the new HDD partition with Dos and Select "Mark Partition as Active".
Activating that partition was the final piece of the puzzle for me. Once I did that, I reinstalled the HDD into the laptop and was delighted to see DOS 7.1 come up, followed by a C:\. I then proceeded to follow William's instructions and ran c:smartdrv.exe and c:\i386\winnt.exe. I watched with amazement as Windows installed flawlessly back onto my dead laptop.
Thanks again, William. You performed a great service!