How to Do a Clean Install - 6 Easy Steps

Updated on October 14, 2016

Why Install Another Operating System?

There are several reasons why you might want to learn how to do a clean install. Maybe you need a fresh start or an update, or simply a change.

However, one of the most common reasons is that the old operating system began to malfunction in some way; perhaps it was infected with a virus that proved too difficult to eradicate, or perhaps a registry error prevented the computer from working properly. Once, my Windows 7 OS failed to update, which boggled the registry and put the computer in an infinite boot-up loop. Needless to say, my only option was a clean install.

Whatever the reason, the steps to do a clean install are fairly simple and, when done right, will leave you with a fresh OS that is ready to use.


1) Gather Your Materials

Although this may seem like a worthless step, it is actually very necessary. Doing a clean install does not have to be a large production, but it can be a large mistake if you do not have all materials gathered beforehand. You don't want to be stuck in the middle of the process, having forgotten something important.

1) Extra blank CD's

2) Flash drive with at least 16 GB of free space - OR - external hard drive

  • For those with large amounts of data on your computer (greater than 16 GB), use an external hard drive.
  • For those with small amounts of data (less than 16 GB), use a flash drive with the necessary space.

3) OS Installation CD's or extra flash drive

4) Permanent, black magic marker

***Details in steps 2, 3 and 4***


2) Backup Your Data!

Before you even think about how to do a clean install, make sure you backup everything you do not want to lose! You will be deleting all traces of your old OS, which includes every bit of your personal data. Use your flash drive or external hard drive to retrieve all data from your computer; copy and paste everything to your external drive.

(Note: It does not hurt to backup your data in more than one place.)

As stated above, for those with greater than 16 GB of data on your computer, use an external hard drive. For those with less than 16 GB of data, use a 16 GB flash drive. Whatever your needs, accommodate for them. If you are using a flash drive, label it with magic marker.

3) Buy or Download the OS Installation

Whichever operating system you choose to install - Windows, Mac, Linux, etc. - make sure you have a copy ready. Windows or Mac installation CD's will work fine, but you also have the option of a Linux operating system. Here I will direct you to a Linux Ubuntu review that I wrote, outlining its advantages over Windows; it is, by far, my favorite OS. However, make sure you also read its disadvantages before installing.

If you should choose Ubuntu, the ISO file is available for free on its website. Simply download the file and burn it to a flash drive (NOT your backup flash drive) using an ISO file burner, which you can also download online for free. (Note: The file must be burned, not copied and pasted.) You may want to try Ubuntu before making your final decision to install it. Label the flash drive with magic marker.

If you should choose Windows, make sure you have the appropriate product key. I have never installed a Mac OS; however, to my knowledge, Mac does not require any kind of product key or activation process.


4) Download a Disk-Wiping Utility

This is where backing up your data becomes very important!

Also called a data destruction program, this utility is specifically designed to overwrite all data on a hard drive. If you choose to do a clean install, your decision must be final. Once this program is run, no data can be recovered from your hard drive; every bit of information will be gone. USE EXTREME CAUTION! THIS CANNOT BE UNDONE!

There are two disk-wiping utilities I would recommend, both free. The first is called Parted Magic, the program I use. It is more of a disk management program, but disk-wiping is also part of its applications. The second program is Darik's Boot and Nuke (DBAN), which is also a thorough data destruction utility.

Whichever one you choose, the process is the same. Download the ISO file off of the site and save it in a location easy to access. Using an ISO burner which you can download free online, burn the file to a CD or flash drive (NOT your backup flash drive or installation flash drive). When the file is completely burned, label the CD or flash drive with magic marker.

5) Erase Your OS

After you gather all materials, backup every bit of your data and own an OS installation copy, then are you ready to erase your old operating system. Get your disk-wiping program ready.

  • If using a CD, open the tray and insert the disk. If using a flash drive, simply insert it into a USB port. Without waiting for it to register, restart your computer and enter its BIOS. You do this by pressing a shortcut key when the first screen appears. The key that you should push varies on different computers, though it is usually f1, f2 or f8. This screen will only appear for a few seconds, so you have to act quickly.
  • Repeatedly press the key until your computer enters the BIOS, after which you should navigate to the screen that displays the computer's boot-up arrangement. Follow the instructions to move the CD or flash drive option to the top of the list, so that your computer will boot up from that option first.
  • Once that is done, save your settings and exit. Turn off your computer and reboot.
  • An unfamiliar screen will be displayed. For either data destruction program, simply follow the instructions to navigate to the program.
  • For Parted Magic users: Once the program's desktop is displayed, search around for the "Erase Disk" option. Choose the "Internal" option and obey any instructions that follow (i.e. you may have to put the computer to sleep). Choose "no" when prompted for the advanced method. Wait until the program completes, which should take only a few hours.
  • For DBAN users: Simply type "autonuke," press enter, and wait for the program to complete. There are more thorough erasure options, but the standard "autonuke" will be sufficient. Typically, DBAN takes longer than Parted Magic to complete.
  • IMPORTANT: You must make sure the program is not interrupted. If the computer turns off while it is running, this may result in a "bricked" hard drive. In this case, data can no longer be copied to the hard drive, rendering it useless. You will need to buy another and replace it manually. Ensure that the program completes as scheduled.


6) How to Do a Clean Install

Installing your new operating system is simpler than it sounds.

  • Once the program completes, eject the CD or flash drive. Turn off the computer and reboot. Eventually, a black screen should appear, displaying a statement that informs you that there is no recognizable hard drive installed OR that there is no operating system. This is good; it means your hard drive is completely empty and like new.
  • Insert the new OS installation CD or flash drive. Turn off the computer again and reboot. (Note: You may have to enter the BIOS again to change the boot-up order.)
  • Assuming you have done everything correctly, an installation screen should appear according to your chosen operating system. Follow the instructions for installation.
  • Congratulations! Once all product keys have been entered, all settings adjusted and all data copied onto your computer again, you have a new operating system! You have successfully performed a clean install!
  • (Note: Once everything is done, you should enter the BIOS again and make sure the boot-up order displays the hard drive at the top.)

Questions, comments or suggestions?

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    • profile image

      buhari abdullahi 2 months ago

      how do i solve the problem of the computer that start working slowly soon after installing the windows?

    • profile image

      DavidtoJohnson 18 months ago

      Excellent Article, with a rich source of information. Old data present in our Desktop/Laptop was always important to us and we never want it to go in wrong hands who can misuse it.

      If our system slows down, it needs to be formatted, but before that, a proper backup of data must be kept with us for again usage of data in the future.

      Further, we have to destroy our existing data with some standard process so that it can’t be recovered back again by any means. Various data erasure software is available which can safely and securely erase out data by overwriting it with many passes. You can try BitRaser software which can completely destroy our previous data out of the scope of data recovery.

    • jabelufiroz profile image

      Firoz 4 years ago from India

      Useful article on operating system installation. Voted up.