start-up diskette or CD

From Windows XP,
Right click on the floppy drive in either My Computer, or Windows Explorer.

Select Format.

Check the box to make a MSDOS startup disk.
I don't recall if this disk includes scandisk.
I believe it includes an updated version of chkdsk.

There are links to several methods to create a bootable CD posted at www.bootdisk.com

Note: if a drive is formatted as a NTFS volume, the DOS startup disk will NOT be able to access the drive.
You will need a 3rd party utility such as one from www.systeminternals.com to allow DOS to access a NTFS volume.
You will have read only access, and will not be able to format the drive unless you run fdisk and delete the non-DOS partition and start over.
Fdisk is a DOS program, and only works with FAT volumes.

If you need to boot a system from floppies to install XP, you need to download the startup disk creation utility from Microsoft.
There are 4 different versions depending on the version of XP. (Home, Pro, W/SP1 W/O SP1)

Your XP CD is bootable and has several utilities to help repair problems with a XP installation.

What I do, is I have a secondary IDE controller, and a hot-swap bay on my main PC.
When I want to setup a drive, I install it in a hot-swap tray, and use XP's Disk Manager to partition and format the drive.

Chas