Theoretically, if you can boot from the windows install CD (perhaps go into the bios to set the proper boot order?), you can then remove all partitions on the harddisk. This will then allow you to "reclaim" the disk, by creating new partitions and formatting them.
All this partitioning and formatting can be done from the Windows setup program, without any need for such ancient things as "DOS". But if you must, you can try a MS-DOS boot disk, use FDISK to remove the partitions, and then set up windows from the CD.
However, if you do any of the above, your harddisk will be wiped, including all the data on it. Depending on your goal, this might not exactly be what you want.
