How to erase my hard drive and start over

Updated: 08/08/2017 by Computer Hope

Computer hard driveMost computers either provide CD or DVD discs, or have a built-in restore process on the hard drive, to reset the computer back to the original software it came with when purchased. Resetting, or restoring, a computer can help eliminate issues with computer software, including corrupt program files and virus infections. Instructions on how to restore your computer back to the original software are provided below.

Warning: Restoring your computer will erase all of the information on the hard drive and make it like new. Once the steps below have been completed, you will not be able to reverse the steps if you want to recover possible lost data. You should back up any personal files you do not want to lose before proceeding with the restore process.

Tip: If you only want to erase the hard drive on your computer and not restore the original software, see our page on how to format a hard drive, SSD, or USB flash drive.

Erasing the hard drive and reinstalling Windows

Click on a link below for instructions on how to erase the hard drive and reinstall Windows.

Tip: If you have an OEM computer (Acer, ASUS, Dell, HP, etc.), it's likely that you have a hidden system recovery partition and don't need to use any CD or DVD to restore your computer.

Windows 10

  1. Open the Start Menu.
  2. Select the Settings option (looks like a gear).
  3. In the Settings window, select the Update & security option.
  4. Select the Recovery option in the left navigation pane.
  5. Click the Get Started button in the "Reset this PC" section.
  6. Choose either the Keep my files or Remove everything option, depending if you want to preserve your personal files or delete everything and start over.
  7. Follow the prompts to begin the recovery process.

Windows will be reset, either keeping your personal files intact or erasing everything, depending on the option you selected.

Windows 8

  1. Press the Windows key plus the "C" key to open the Charms menu.
  2. Select the Search option and type reinstall in the Search text field (do not press Enter).
  3. Select the Settings option.
  4. On the left side of the screen, select Remove everything and reinstall Windows.
  5. On the "Reset your PC" screen, click Next.
  6. On the "Do you want to fully clean your drive" screen, select Just remove my files to do a quick deletion or select Fully clean the drive to have all files erased.
  7. On the "Ready to reset your PC" screen, click Reset.

The hard drive will be erased and Windows 8 will be reinstalled.

Windows 7 and Vista

To restore a Windows 7 or Vista computer, you must have a set of restore discs for the computer or an original Windows 7 or Vista installation disc. If you do not have a set of restore discs, you will need to contact the computer manufacturer to order a new set or restore discs.

Note: Before following the steps below, make sure the computer is set to boot from the CD-ROM drive.

  1. Insert the Windows 7/Vista installation CD in the CD-ROM drive and restart the computer.
  2. When you see the message "Press any key to boot from CD," press a key on the keyboard.
  3. Press the Enter key at the Windows Setup welcome screen.
  4. When prompted, press any key on your keyboard.
  5. On the "Install Windows" page, select your preferred language and other preferences, then click Next.
  6. On the License Agreement page, accept the terms and agreements and click Next.
  7. On the Installation Type screen, choose the Custom option.
  8. Select the Drive Options (advanced) option.
  9. For Disk 0, delete all partitions. When all partitions have been deleted, you should see a single entry named "Unallocated space."
  10. Click on Disk 0 and select Next.

The Windows installation process will start by creating a new partition, formatting the partition, and installing Windows on the hard drive. The formatting process will erase the hard drive before installing Windows.

Windows XP and 2000

To restore a Windows XP or 2000 computer, you must have a set of restore discs for the computer or an original Windows XP or 2000 installation disc. If you do not have a set of restore discs, you will need to contact the computer manufacturer to order a new set or restore discs.

Note: Before following the steps below, make sure the computer is set to boot from the CD-ROM drive.

  1. Insert the Windows XP/2000 installation CD in the CD-ROM drive and restart the computer.
  2. When you see the message "Press any key to boot from CD," press a key on the keyboard.
  3. Press the Enter key at the Windows XP Setup welcome screen, then press F8 to accept the Terms and Agreements.
  4. Follow the on-screen instructions to select a hard drive partition to format and install Windows XP on.
  5. After formatting the hard drive, which will erase all data, click on one of the links below for steps on how to install Windows XP or Windows 2000.

MS-DOS 5.0+, Windows 3.x, 95, 98, ME, and NT 4.0

  1. Place the bootable diskette or disc inside the computer and reboot to get to the DOS prompt. In some cases, you may need to boot the computer with CD-ROM support or press a key to boot from the disk.
  2. At the MS-DOS prompt type, format c: /s

Note: If the "format c: /s" command does not work, you may need to download the format.com file to your boot disk.

  1. The computer will ask you "Are you sure you want to erase everything on drive c:"
  2. If you are ok with doing this, press "Y" for yes and press Enter.
  3. After doing this, the computer will begin the formatting process. While the computer is formatting, make sure no errors are encountered.
  4. Once the format process is completed successfully, at the MS-DOS prompt, type fdisk /mbr and press Enter. This should return you back to the MS-DOS prompt with no message. This step is not required but recommended.
  5. Once back at the MS-DOS prompt, reboot the computer with the boot disk still inserted and follow the steps below if you want to re-install Windows on the hard drive.

Installing earlier versions of Windows and DOS after formatting drive

Windows NT 4.0

Windows NT can be installed different ways. We recommend that Windows NT be installed using the steps below as we feel that these steps by far are the easiest way to install Windows NT 4.0.

First, we recommend that all users wanting to install Windows NT use the /b switch, which allows the users to not need to create the diskettes. We do, however, recommend that the user create the emergency recover diskettes if they have not already been created after the installation of Windows NT.

Finally, before the installation of Windows NT, it is recommended that you run SMARTDRV, which helps the installation of Windows NT run a lot faster.

  1. Place the CD into the computer.
  2. Type X: (where x is the CD-ROM drive, often this is D:).
  3. Once at the appropriate drive, type CD WINNT and press enter to get into the Windows 95 directory.
  4. Once at X:\WINNT> Type winnt /b.
  5. Follow the on-screen instructions to complete the installation.

Windows 98

Windows 95 with CD

  1. Place the CD into the computer.
  2. Type X: (where x is the CD-ROM drive, often this is D:).
  3. Once at the appropriate drive, type CD WIN95 and press enter to get into the Windows 95 directory.
  4. Once at X:\WIN95> Type setup to begin the installation
  5. Follow the on-screen instructions to complete the installation.

If you are encountering issues during the setup process, you can add additional switches to the setup command line. These switches can be found on our Windows 95 setup switches page.

Windows 95 with floppy diskettes

  1. Place the first diskette of Windows 95 into the computer.
  2. At the A:\> Type setup and press enter to begin the installation.
  3. Follow the on-screen instructions to complete the installation.

Windows 3.x

  1. Place the first diskette of Windows 3.x into the computer.
  2. At the A:\> Type setup and press enter to begin the installation.
  3. Follow the on-screen instructions to complete the installation.

MS-DOS

  1. Place the first MS-DOS diskette into the computer.
  2. At the A:\> Type setup and press enter to being the installation.
  3. Follow the on-screen instructions to complete the installation.