Alternatively referred to as a boot disc, system restore disc, restore CD, recovery disc, and recovery disk, a restore discs is a CD or DVD included with many OEM computers. This software reverts the operating system back to how it was when the computer was originally purchased. Using these discs often makes reformatting easier for most users because all of the settings, drivers, and requisite software are included. Today, many computer manufacturers (Dell, Hewlett Packard, Toshiba, etc.) ship a recovery disc with their products or allow you to create one.
Tip: Many of the new computers no longer come with a restore disc or CD. To restore these computers, use the hidden recovery partition.
Lost restore disc
If you have lost your restore disc and don't have a hidden partition, contact your computer manufacturer for a replacement. If your computer manufacturer is out of business, you may be able to find restore discs through an online auction site or a third party website that specializes in restore CDs. Alternatively, you can purchase a copy of Microsoft Windows or other operating system and install it onto your computer.