XP frustration: Can't make "C" partition!

Two of my five Windows computers won’t let me set up a “C:” drive/partition, and it’s driving me crazy!

Both of the systems in question run XP Pro SP3, and XP is installed and running from Drive 0 / Partition 0 on all of them. But on those two, the system won’t give it drive letter “C:”. Neither of those two systems has a Drive “C:” at all.

On one system, disk 0/part 0 is called Drive “E:”, but the system insists on putting the page file on drive “T:”. The other is similarly split, and I find that irritating.

The “Computer Management (Disk Management)” display shows disk 0/part 0 as “Healthy (System)” and disk 0/part 6 “Healthy (Page File)”.

**How can I force disk 0/partition 0 to be given drive letter “C:” and force it to hold both the system and the page file? **

I realize that’s not absolutely necessary, since XP runs now on this atypically lettered system, but dammit, I want it to have letter “C:” I don’t mind re-installing the system to get it, either, but I have no reason to think that alone will do the trick.

For what it’s worth, I blame a horribly complicated booting system called “BootIt Next Generation” that I previously installed, then fully uninstalled. But removing it then re-installing XP hasn’t helped.

Does anyone know the secret?

What did you use to set up the partitions when you reinstalled windows? Did you wipe the entire disk?

It sounds to me like there’s a hidden partition left on the drive.

My best guess is that you have a card reader or hard disk that is connected via USB (either externally or internally on a USB header on the motherboard).

Disconnect these USB drives, make a new XP installation and reconnect them when it’s finished.

Before doing that however, there is a test you can do.

Without doing any mods to your computer, run the XP installation up to the point where it asks you where you want XP installed. There should be a list of all drives on the computer.

Drive letters are assigned in the same order as this list. So, the first two entries are what are taking up letters C and D. If these are USB devices, disconnect them and re-run the installation. Then drive0/Partition 0 should be at the top.

Go to Computer Management then choose Disk Management.

You will see all partitions for all drives on your computer.
You will see what drive letters are assigned to each partition.
When a partition doesn’t show a drive letter for it, it has none. You can assign it one to make access easier.
You can assign a second drive letter to any partition that already has one. If C: is not in use by any other device you will want to right click on the partition with the OS and choose Change Drive Letters and Paths. Choose the add button and add in C: for it. It will now be both accessible as C: and E:, but without E: the OS and other programs will not work, because they reference E: in their paths not C:.

I use Acronis Disk Director, and it reported there were no hidden partitions. BootIt NG created it’s own boot partition, but after I uninstalled it, I deleted that special partition, too.

Once you get into Windows, you can use the Disk Management tool to change drive letters, but it won’t let you change the drive letter of the system volume. If there were some way of giving the system volume drive letter C from outside Windows, such as with the Recovery Console, that would probably work. Does anyone know any way to do that?

Note that Drive C is completely unassigned and therefore is available.

That’s not the case in these two systems. Not only do I almost never use USB devices and never at all when booting or installing Windows, Drive C remains fully available for assignment.

Did you delete the partitions when you ran the next windows reload? (I only ask because I don’t remember reading you specifying that.

If not this boot tool you used may have done something wonky to the drive.

What you are describing is common behavior for an install with a card reader or external drive plugged in, but outside of that this is extremely weird.

I had to enter the Recovery Console to see the list, and the first system lists Drives C, D, and H as allowable Windows installations to choose from to issue any commands.

I was surprised to see a Drive C in that list, since it definitely does not show up under Windows. Note that I have no USB devices connected except the keyboard, which is always the case (I almost never use USB devices like flash drives, and I have no USB printers, either).

I then issued the command: bootcfg /add

The output listed 4 Windows installs, which were:

along with 2 other G:\pebuilder3110a\Bart_PE entries.

What should I do under these circumstances?

Then you obviously have not deleted all of the partitions before the reinstall.

One of these other partitions is probably interfering with a C: drive assignment.

Kill all partitions and reload clean.

I did not delete the other partitions, since they contain necessary data.

I deleted the partition at Disk 0 / Partition 0, created an empty new NTFS primary partition there, and re-installed Windows XP. I can’t recall with certainty, but I’m pretty sure the Windows installer named it Drive C for the install. But by the time I booted the newly installed Windows partition, it had changed drive letters.

I’m perfectly willing to re-install Windows from scratch, but I need more confidence than I have now that it will receive drive letter C. I cannot delete those other partitions, but I don’t mind unplugging the drives which contain them for the new install of Windows on blank drives. How confident are you that I’ll have success with that approach?

Are you installing onto an IDE drive? I don’t know how SATA works, but for IDE it’s (I think) two hard drives per IDE socket; one master and one slave. Moreover, each socket has a number: 0, 1, 2, etc.

If you put two drives on socket 0 and two on socket 1 (thus 0:0,1 and 1:0,1) and then try to install Windows to 1:1 you are not going to get Windows on drive C: unless the first three drives are unpartitioned.

If I were trying to deal with this, I’d pull all the drives except the one you want to install to, install Windows, and then try to re-install the other drives. And hope.

Or install Linux.

Because, basically, the core parts of Windows were designed in an era in which a)PCs had an A: drive and a B: drive so we could copy floppies (thus C: as the first hard drive) and b) Microsoft could not imagine that anyone would want more than one drive or that anyone would actually open up their PC and fiddle with it!

Technology sucks only slightly less than no technology.

I haven’t used IDE drives in years, so they’re all SATA. Even so, they nevertheless have an order. I have disk 0 plugged into SATA slot 0 and set that disk first in the disk and boot order in the BIOS.

Nevertheless, I’d decided that I’d disconnect all physical disks but the disk I will re-install Windows to from scratch. But that’s so close to what I did the last two times (which resulted in disk0/part0 not being given drive letter “C:” and in fact no partition got drive letter “C:”) that I’d like to have more confidence that will work definitively. So what I was hoping for was someone who confidently knew the detailed technical arcana of exactly how drive “C:” is assigned.

I take it a completely blank hard drive is alright with you, and nothing you must keep is on the hard drive.

Delete the partitions.
Rewrite the master boot record.

That should remove the boot manager and The OS will install as drive C: in one partition that it will create for you.

Use whatever you want to do the above. You can use the line commands after booting from the XP cd or use a utility. You will probably find a utility to do this is easier. You want to write a new mbr to make the hard drive function how you expect.

That’s how I have always done it, and never had any problems.

Is this the same computer your asking about in the other RAID thread? If so it’s important to know that. As far as I know XP can not boot on a dynamic disk which is used for striped disks. You’re working with a different system than this thread implied then, in which case disregard any advice I gave.

I suspect that your problem is a dodgy partition table.

Partition Tables are a very simple data structure on disk

PartA ___ StartA:FinishA
PartB ___ StartB:FinishB
PartC ___ StartC:FinishC
PartD ___ StartD:FinishD

However, there are some rules, and the most important are that StartA<FinishA<StartB<FinishB<StartC<FinishC<StartD<FinishD and
PartA is populated before PartB before PartC before PartD

A fair amount of software available sees fit to ignore these rules, just changing the partition table in any manner that it sees fit. So while your disk started out as

PartA: Boot Manager
PartB: System
PartC: Data
PartD: …

it may now look like
PartA: …
PartB: System
PartC: Data
PartD: …

and XP install is getting confused by the missing PartA. I’ve seen similar things happen before, and the only solution is a backup (if you have any real data on the system), deletion of the entire partition table using something like Ranish Partition editor (fdisk probably won’t work properly), and start again.


I would be very interested in what a real partition manager has to say about the partition layout, vs. what Windows says. If there is a non-windows or hidden partition on the disk before the D: partition, Windows will ignore it.

Download 7tools partition manager and have a look at the actual layout of the disk.

Only if it is a properly defined partition - with the flags set correctly. If it is an empty or null partition, XP partition handling often fails to work correctly.

As I (and sweepkick) said above, a proper partition tool that shows what is really there (and not guess like fdisk) will probably make things clear.


Definitely unplug the other drives for the duration of the install. If you are using a blank drive with all partitions deleted, there is no reason why you should not get a C: assignment to the primary partition.

For the record, I own a computer shop, we do this several times a day and I have never seen a drive with all partitions deleted fail to deliver a C:.

Any time I have seen the scenario you describe was another drive/partition scooping it up.