There are 2 partitions in my computer: C drive and D drive.
C: contains Windows98, while D: has just been formatted with
the command "format /s d:" so that D: is bootable.

Recently whenever I boot up the computer with C:, the following
error message displays, therefore I can only use D: to boot
up the computer.
Type the name of the command interpreter

Although I can use D: to boot up the computer, I cannot make
access to the data in C:. Whenever I try to access the data,
an error message will be shown as follows:
D:\> C:
C:\> dir
Invalid media type reading drive C
Abort, Retry, Fail?

It seems that my computer can't recognize C:, how can I solve
this problem please? And, as I have got important data stored
in C:, I can't format/fdisk it at the moment. Is there any
method I can backup the data before I format the harddisk please?

Many thanks.

Boot from an emergency Win98 floppy and type
sys c:
That restores the system files
if that doesn't help....type
fdisk /mbr
That restores the Master Boot Record

Helloa. Run "FDISK" at the command prompt. Then choose option '2' to "Select Active Partition". After that, if you see the two partitions "C & D" set the "c" to be active. Then reboot.

Comments: choose option '4' to check the number of partitions you have.

Danty,

Thanks for your answer. :)

However will "fdisk /mbr" destory the data stored in C: ?

No

that wont werk fred... "invalid media...." means that the puter can't recognize the hd...
u can try formating C: if that doesn't werk...

then u *have* to use fdisk to erase the partitions..then create new ones...then format both drives

Thanks all for your reply.

As I have important data stored in C:, I can't format the HDD right now.

Sorry that I am not familiar with the FDISK command, may I ask whether FDISK will erase data stored in my harddisk please? Can I use Danty's method without deleting the data in C:?

Thanks again.

I do not have all the info from you to advise exactly. I am wondering if the partitions on drives C and D are different formats.....i.e one is fat 16 and the other fat32.I had a similar problem at one time because I manually accepted the 'normal' option in the bios on HD detection when I should have accepted LBA. The drive then reported 'invalid media track'. It is always best to set the bios HD detection to AUTO and let the computer deal with it.

When you used the FDISK did you say yes or No to FAT 32 option on the first screen(assuming that you used a WIN 98 version of FDISK).If the C drive was originally FAT32 and you said NO to the FAT32 option when you ran FDISK, this can give you similar problem depending on what you did in FDISK.

What I suggest is that you boot up from a Win98 floppy made from a machine running fat32. Do not use old fat16 only system disk (pre WIN98) as this will lead to not recognising fat32 format(invalid media error). Make sure that it has on it FDISK.exe. By the way, certain usage of this programme WILL lead to destroying all info on your drives so BE CAREFUL(although you usually get a warning). At the A: prompt type C: If you get 'invalid media error' return to A: prompt. Now type FDISK. When asked whether to accept FAT32 say yes. Now select option 4 and press enter. This is a safe option and will not harm any data on your computer. See what format drive C is reported as having(fat 16 or 32). Now say yes to the question to view logical drives. Are they the same as drive C:? Report back to erceive more help. Remember it is important to set the bios to Auto detect hard drive before you boot up.

Best of luck

Below has been cut and pasted from computing.net Advanced How To's Partitioning and formatting
************************************
5.Reboot: Reboot the system using either the Reset button or the ({Ctrl}+{Alt}+{Delete}). Make sure the floppy disk is in its drive, since you still need it. Note that you may get "Invalid media type reading drive C" errors while rebooting. This is normal at this stage.

How do I troubleshoot a computer running Windows® 95 or 98 when it will not boot to the hard drive?

Problem

Your computer will not boot to the hard drive. One of the following error messages may appear:

Non-system diskette. Replace and press any key to reboot.

Invalid system disk. Replace and press any key.

Insert Bootable Media.

Operating System not found.

Missing Operating System.

Discussion

This article assumes that your system will power on and that Power-On Self-Test (POST) initializes, but the system does not attempt to load Windows. On some systems, the completion of the POST is indicated with a single beep, prior to the Windows screen. If it appears that Windows attempts to load and then freezes or produces an error message, refer to the following Dell Knowledge Base Articles:

TT1036625 - "How do I troubleshoot a system that will not boot into Windows 95 or 98?"
TT1012430 - "Why will Microsoft® Windows not start in Normal Mode after I install new software on my computer?"

Solution

To resolve the problem, perform the following steps:

Remove any floppy diskettes from the floppy disk drive.
If there is a floppy diskette in the floppy drive, reboot the system after you remove the diskette. If the error persists, proceed to the next step.
Verify that the hard drive is recognized in the System Setup screens, or Basic Input-Output System (BIOS).

For instructions about how to enter the BIOS, refer to Dell Knowledge Base Article: TT1012573.
To verify that the hard drive is receiving power, refer to Dell Knowledge Base Article: FA1011055.
To troubleshoot BIOS detection of the drive, refer to Dell Knowledge Base Article: TI1014125.

If the hard drive is recognized in the BIOS, proceed to the next step.
Watch for specific error messages that occur during or after the POST.
If an error message appears, search the Dell Knowledge Base for information relating to the specific error message.
Execute the Dell 90-90 Hard Drive Diagnostics. For more information, refer to the following Dell Knowledge Articles:

TT1022211 - "How do I run the 90-90 Hard Drive Diagnostics on a Dell portable system?"
HO1030780 - "How do I run the 90-90 Hard Drive Diagnostics on Dell OptiPlex™ and Dimension™ computers?"

Locate your Windows Startup diskette and write protect the diskette.

NOTE: In order to write protect a diskette, move the small plastic tab on the back corner of the diskette to an open position. One end of the diskette should have two small, open squares in each corner after you have protected the diskette.

For alternative boot diskettes, refer to Dell Knowledge Base Article: FA1014475 Title: "What can I use for a boot disk with CD-ROM support?"

Turn off the computer and insert the Windows Startup diskette into the floppy drive. Turn the system on.
Depending on the type of diskette you are using, a startup menu may appear. Select Start computer without CD-ROM support.
At the command prompt, type C:\ , where is to press the key once.
If the C:\ prompt appears without error, proceed to step 10.
If errors occur, proceed with the next step.
At the command prompt, type the following commands and press the key after each command:

A:\
FDISK /Status

If FDISK reports the message No Partitions, then you must partition the hard drive. After you partition the hard drive, proceed to step 13. For partition instructions, refer to Dell Knowledge Base Article: FA1011782.

NOTICE: All data on the hard drive will be lost when you repartition or format the hard drive.

If FDISK is unable to partition the hard drive successfully, then contact Dell Technical Support for further assistance. Refer to the E-Mail Dell section at the end of this article.
If FDISK reports valid partitions (no errors are returned), proceed to the next step.
At the command prompt, type SYS C:\ , where is to press the Enter key once.
The message System Files Transferred should appear. Remove the floppy diskette and reboot the system. Proceed to the next step.
If the message System Files Transferred does not appear, proceed to step 13.
The system should boot to the C:\ command prompt.
If it does, refer to Dell Knowledge Base Article: FA1014470 to rebuild the MSDOS.SYS file and the problem should be resolved, though you may have suffered some data loss depending on the root cause of the problem.
If the system does not boot to the C:\ command prompt, proceed to the next step.
Insert the Windows Startup diskette into the floppy drive and restart the system.
At the command prompt, type FORMAT C:\ /S , where is to press the Enter key once.

NOTICE: All data on the hard drive will be lost when you repartition or format the hard drive.

NOTE: If you are using a Windows 98 Startup disk, the FORMAT command is on the RAM drive that is created when you boot to the diskette, normally D:\. You must type D:\ prior to typing the format command.

If the hard drive will not format or if it returns an error, contact Dell Technical Support. Refer to the E-Mail Dell section at the end of this article.
Once the format has completed, remove the floppy diskette from the floppy disk drive and reboot the system.
If the system boots to the C:\ command prompt, proceed to reinstall the operating system and your other applications. Search the Dell Knowledge Base for instructions.
If the system does not boot to the C:\ command prompt, contact Dell Technical Support at:

E-mail Dell

For more troubleshooting assistance, you can communicate by e-mail with a Dell Technical Support Representative. Navigate to the following link and select the option that best describes your problem:

http://support.dell.com/us/en/emaildell/

--------------------------------------------------------------------------------

Keywords for this Document:

Boot | Bootable | drive | Hard | Insert | Media | no | TI1014140

Details

Dell Troubleshooter

Document Number:
TI1014140

Current Status:
Complete

Last Updated:
11/8/2000

Document Audience:
Internet

Document Author:
David Pimentelli

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All the replies have me confused. Invalid media type used to mean the hard drive was larger than the OS could access.
So I am guessing that C: is FAT32 and D: is FAT16. Unless you can find something with
FDISK /MDR you have a problem. Trying to SYS C: from a floppy disk seems like a good idea too, but I have no experience with FAT32.

You really should try partition Magic. Use it to convert the file system on C: to FAT32 if it is not.

Also: do you know if COMPRESSION was enabled on C:??? If so, fdisk shows the file system type as "UNKNOWN". don't know if this would be the problem or not, though.