I'm planning to give away my Gateway desktop (about 3 yrs old) and want to completely clean out my hard drive. My bios is set to boot from the CD-ROM, and I have all of the original installation files, including the XP OS. However I got the message that it can't install the system, since the OS on the CD-ROM is an "older" system than what's on the HD. Of course, I've downloaded over the last few years the Service packs 1 and 2, so now it won't boot.

Is there a way to easily just reformat the hard drive, then reinstall the older XP file? Everything is backed up on an external Hard Drive.

you should be able to format and repatition the hardrive during the install

instructions here

1. Start your computer and then insert the Windows XP CD into your CD-ROM drive.
2. Your computer should automatically detect the CD, and a message "Press any key to boot CD" will be displayed for 5 seconds.
3. Press a key and the CD will begin to load files that are needed to begin the installation. This make take a few minutes.
4. When asked if you wish to install Windows XP press Enter.
5. You will be presented with the End User Licensing Agreement. Press F8 to accept and continue or press F3 to cancel the install.
6. Select the partition in which you wish to install Windows XP and press the Enter key. If you wish to delete the current partition or partitions you can do so now. Once you've deleted partitions you will be asked to create a partition. At this point you can choose the size you wish. Most people will elect to create one partition that fills the entire dive. If you decide you would like multiple partitions then create a partition size that will be suitable for XP and your installed apps as well as room for cache files etc. 10GB is s nice size for a full XP install leaving plenty of room for applications etc. After XP is setup and running you can create additional partitions in the free space through XP's Computer Management Console.
7. The next screen asks if you wish to use the NTFS file system. This is the preferred file system, however, if you choose to use FAT32, you will not have all the security and stability features of Windows XP.
8. If you previously had an Operating System installed you will be given a choice of Format options . Select the Format option of your choice. When asked to start the format, press the "F" key. The formatting process may take quite a bit of time.
9. Setup will begin an automated loading of files which will take several minutes.
   ***Note - If you are clean installing using an XP Upgrade CD you will be asked for a qualifying product at this point. Just pop the CD for your older version of Windows into the drive while the XP setup completes an authenticity check. Following this you will be prompted for the XP CD and setup will continue.
10. After this is complete the computer will restart. Leave the XP CD in the drive but this time DO NOT press any key when the message it "Press any key to boot CD" is displayed. In 5 seconds setup will continue.
11. The Windows XP Setup wizard will lead you through the process of gathering information about you and your computer.

I've tried those steps but the computer (which is set to recognize the CD-ROM) won't deal with the disk since it's the original disk, and the message says it's an older version than what's on the computer. It does ask to boot from the CD-ROM, I say okay, but it then bypasses it.

Is there a way to reformat the HD and do a new install from the CD=ROM?

you could make a boot floppy disk or cd and format the hard drive you can get a boot disk from here Bootdisk.com. then reinstall the windows. Boot from the boot disk and type format c:\ and press enter

Thanks. I looked at that site but was not sure which file to download. It's a NTFS system. And once you boot, are you then into the c: drive? If that's so, then I assume I can reformat the drive, and then install the XP files.

Hi fgrayson

Welcome to PC Help Forums

Can I ask why you would want to part with your PC with an Operating System still on it?
What if the other person wants to put something else on?
Here's how to wipe the drive before getting shut.
Go to Bootdisk.Com and obtain a 98se boot disk, get the one that has a Ram Drive.
Enter the bios and set the first boot sequence to A (Floppy), save and exit.
Insert the 98 floppy and when it gets to the A prompt like so A:/ type Fdisk.
It will ask if you want to enable large disk support and it will also inform you that NTFS is the file structure.
Say yes to large disk support and in the menu that follows DELETE all Non Dos partitions.
It will warn you that all data will be lost, proceed y/n? Press yes.
Create a new fat32 partition and then you can format by typing at the A prompt Format C: there is no / switch.
It will say Warning all data on drive C will be lost do you want to continue?
Press yes.
It will ask for a Volume label just hit enter.
That's it.

For a more detailed explanation look here:
RADIFIED FDISK Guide: Doc's Hard Drive Partitioning Tutorial