Dell Dimension 8400 Hard Drive Replacement: No Windows XP Cd provided

I second the opinion of imaging the existing drive to the new hard drive.

Regarding a non-Dell XP install CD, Dell keys will work with OEM discs but not with retail ones. If a retail disc is used, a retail key must be used but should not be activated; once the install is complete, the Microsoft product key change utility should be used to switch the product key to the key of the Dell COA.

To answer your last question first, this page will lead you to the instructions on installing your operating system:  Restoring or Reinstalling Windows on a Dell.  A manual install is covered in the third option on that page.

With regard to having no Windows CD, if you live in the U.S. you should use this form to request a replacement for your operating system CD:  Dell Replacement Disk.  There may be a charge for this service.  If you do not live in the U.S., I'm afraid your only choice will be to contact Dell Technical Support for your region directly and request the disk.  Use the information needed in the U.S. request form as a guide to what you will need to provide to the Dell Representative.

You can use any 3.5" SATA desktop hard drive as a replacement for your old drive up to a capacity of 2 TB.  The only thing I would stay away from on a Windows XP machine is the Advanced Format drives as these require special handling to be used with that operating system.  The 2 TB limit is due to the fact that Windows XP only uses the Master Boot Record scheme of partitioning on hard disk drives.  Larger drives must be partitioned using the GPT partitioning scheme which Windows XP 32 bit does not understand.

If you use a Dell labeled installation CD to install Windows XP on your computer you should not need to worry about the product code for activation.  Dell installation disks are automatically activated at the time of installation.  If you use a standard Windows XP disk, or decide to update your system using Windows 7, you will need a new product key as standard installation disks do not have the necessary code to check for the Dell BIOS signature.

One additional issue you will need to consider when you are ready to install; the Dimension 8400 uses SATA hard disk drives and has an AHCI setting in its controller.  Most Windows XP installation CDs do not have a driver for this mode.  When Windows XP setup tries to install files to your hard drive you will get a message that setup cannot find any eligible disk drives for the installation, Stop: 0x0000007B.  The easiest work-around for this problem is to go to System Setup (F2 during the Dell screen after starting the computer) and set the SATA configuration to RAID Autodetect/AHCI.  Most people can't tell the difference between this setting and the AHCI alternative; all it does is set the SATA controller to a translation mode that makes the SATA hard drive look like a standard PATA/IDE/ATA drive.  In this mode the IDE mass storage drives native to Windows XP will see the drive and the setup application can install the system.  Installing Windows XP using the AHCI controller usually means you must make an installation CD by slipstreaming the AHCI drivers into the files already on the Windows XP setup disk and writing out a new CD.

EDIT:  Forgot one thing; as your present hard drive is still working you might want to consider using an imaging program such as Acronis True Image to clone your existing hard drive.  If you purchase a Seagate or Western Digital hard drive you can download a crippled version of this application from either vendor, though you must have a Western Digital drive to use its version and a Seagate drive to use the version from that vendor.  The only thing I don't know is if these versions support a feature that allows you to adjust the size of the cloned partition.  The purchased version of Acronis allows you to fit the image onto a new drive having a different size from the original, provided the new drive has at least the capacity occupied by the information on the drive.  I would still order the Windows installation CD, but cloning the drive would make things much faster and less troublesome.

The 8400 has (or had) the windows 25 character key on a small sticker on the tower. Mine has it on the left side. You can borrow a Dell xp disk that is the same version--home, pro, mce--as yours. Lots of those disks out there. Use your own key if it is asked for one. I'm not sure if Dell is still sending out replacements disks for XP since support for it is discontinued. Don't forget to install the Desktop System Software first along with the chipset drivers or all the other drivers won't install. Dell Drivers and Downloads has what you would need. support.dell.com/.../index.aspx

We're very happy to learn that you have it working again however you made it happen.

Best of luck to you!