Windows setup needs an active formatted partition, and a brand new hard disk hasn't got any..
People also like to add hard drives to their machine, for good reason.

So... Let's start talking about

RE-PARTITIONING / PARTITIONING

FDISK uses a DESTRUCTIVE METHOD, DATA GETS WIPED
Doing this while more than one drive is hooked up is kind of risky, but this is, after all, what this topic is about...
Still, you can disconnect the old system drive if you don't want to mistakenly delete or re-partition the wrong drive.

WARNING: You should not run FDISK from within a DOSBOX in Windows.

Another word of warning.
You may think the drive on IDE1 master is system disk C:
This is not always the case.
You have to check this, because Windows 9x will set up on the first ACTIVE it finds and can set up on.
Sidenote; in dualboot; if the active partition is NTFS, it should go for another partition. It's much better to first do win9x, and then w2k, or XP, though..
Sidenote two; NT4 requires a FAT16 partition for dualboot.

Before you start partitioning a harddisk, consider this;
Whenever you can, you should consider the MANUFACTOR DISK TOOLS.
Some of those they provide at their website can save you a LOT of time.
You can use them on a used hard disk too, and it will warn you that all data on the drive you let it do its thing on will get lost.

Another sidenote: When you get the drivemanufactor tools, check for compatibility with the operating system you intend to use.
For instance, after you partitioned a drive into NTFS using the windows XP CDROM, earlier versions of maxblast will freak out when you later decide to use maxblast to re-partition.
(the new version is XP compatible by now.)

You can selectively wipe them partitions off with the XP disc, or use wipeout.
(Please note that there is a difference; wipeout simply deletes ALL partitions off the selected drive.
you must know this bit...
fdisk /status tells you what drives are detected, their number, and the letters found on the numbers
... in wipeout... C: is drive 1, D: is drive 2, E: is drive 3 and F: is drive 4... the letters wipout uses in its commandline are irrespective of the reported output when you used fdisk /status to tell you what letters are on the detected hard disks! )

**
Knowledge Base article; How to Use the Fdisk Tool and the Format Tool to Partition or Repartition a Hard Disk.
http://support.microsoft.com/support/kb/articles/Q255/8/67.ASP
I assume you have read the Knowledge base article.
Well, you'll find I've added a few twists, so as to avoid a few pifalls
**

In these procedures I assume you have more than one hard disk, or you want to add a hard drive you want to use as a new disk, and it had to become your C: drive.
I repeat, doing this while another disk with your data is hooked up can be dangerous to your data.
One can disconnect the old hard disk if you don't want to mistakenly repartition the wrong drive...

Whatever the goal... When you add a hard drive, or have to work on a hard drive that has been used before, you should use these initial steps anyhow, and take notes...

One begins, pen and notebloc at the ready...
boot from the EBD or win9x start disk

fdisk /status
esc
fdisk
y
4 (show info on hard disk one.)
esc
5 (option to choose other hard-disk, choose the next number)
4 (info on chosen hard disk.)
esc
5 (you look at all the hard disks... )
4
und so weiter until you have all the details, and then
esc
esc

Yes! DO use a notebloc, and take notes of the results you saw.
You do NOT want to partition / repartition / format any drive by mistake, so you better LOOK, take notes, and be REAL CAREFUL.
If you hit the wrong option and it asks to delete or create a partition, hit ESC and ESCAPE out of there.
You really want to take these notes. You see, doing the above, you may find out about overlay and proprietary disk partitions. And, perhaps even more important, with these notes, you have a good chance to return to the state it was in after a fluke happened.

TIP; TAKE the notes, and remember that notes PLUS a backup of the partition table is even better...
I know flukes happen, and hate data loss..
It is why I mentioned you can get MBRworks or similar utils...)