How to Reformat a Computer Without a Windows XP CD

When damage to a hard drive's file system is so extensive your computer no longer works properly, it may be necessary to reformat the hard drive and start from scratch.
Windows' installation disk comes with a built-in formatting applications. If you are missing a Windows CD, the easiest way to format your hard drive is with an Ubuntu Linux Live CD.
Keep in mind, however, that once you format your hard drive, it will be blank. You will need a back-up image to restore your old system, or else obtain and re-install a new operating system before you can use your computer again.

Difficulty: Moderate

Instructions

Things You'll Need:

• Computer with a CD drive or USB port
• Copy of Ubuntu Live on a CD or thumb drive
• Back-up image of your old operating system or a new operating system

1. Boot your computer from a CD or thumb drive containing a bootable copy of Ubuntu Linux and choose the "Try Ubuntu without any change to your computer" option.

2. Open the Partition Editor application, located in "System" under "Administration" on the top deskbar.

3. Identify the partition you want to re-format on the bar across the top of the screen, which represents your hard drive. Empty space on the hard drive is gray-colored and marked "unallocated." Colorful boxes represent partitions.

4. Click on the partition you want to re-format and click "Delete." Repeat with each partition you want to re-format.

5. Click on "Apply" to finalize your changes if what you need is a completely blank, unformatted hard drive. Exit the program and restart the computer.

6. Click on "New" to create one or more new partitions and re-format the hard drive. For Windows-only partitions, re-format in NTFS format. For Linux-only partitions, choose the ext3 format. For partitions readable by the Windows, Linux and Mac OS X operating systems, choose the FAT32 format. Restart the computer.

7. Install a new operating system from its respective installation CD or restore your old operating system from the back-up image.

Tips & Warnings

• This method will only erase the contents of your file allocation table, which tells an operating system how the drive is partitioned. Your old data remains on the hard drive, and the OS will overwrite it as you save new data. Completely deleting data from a hard drive so that it cannot be recovered requires specialized software.
• Re-formatting will erase all your hard drive's contents. Back up all valuable data before re-formatting. Some computer manufacturers provide a back-up image of the Windows installation that shipped with the computer. In some cases, that image is stored on a special partition on the main hard drive. If you intend to restore Windows from this partition, do not delete it during reformatting.