If your computer has become slow and using it is proving increasingly frustrating, the quickest and easiest solution may be to format it completely. Formatting it at regular intervals, to provide for a new "clean" installation of the operating system, will ensure that it always functions optimally over time. Formatting will free it of temporary files, corrupted or no longer needed, which are the main cause of performance degradation in the long run. By regularly backing up your personal files, the entire format and reinstall process shouldn't take more than a couple of hours.
Steps
Method 1 of 2: Windows
Step 1. Get or create a Windows installation disc or USB drive
The easiest way to format your computer and reinstall the operating system is to use a Windows installation disk or drive. The selected Windows version must be the same as the one currently installed on your system. For example, if you are using Windows 7, you will need the Windows 7 installation disc. You can use the recovery disc that came with your computer at the time of purchase, or you can choose to create a new installation disc yourself. You will need to use a blank DVD or USB memory drive with a capacity of at least 4GB:
- Windows 7: Use your product key to download the ISO file directly from the [https://www.microsoft.com/en-us/software-download/windows7 Microsoft website]. The next step is to find the "Windows DVD / USB Download Tool" software to create the actual installation DVD or USB drive using the ISO file you just downloaded.
- Windows 8: Go to the following Microsoft Windows 8.1 web page, then press the "Create Media" button. Run the program you just downloaded, then follow the instructions that appear on the screen to download the installation file and create the relative DVD or USB media.
- Windows 10: Go to the webpage to download Windows 10, then press the "Download Tool Now" button. Run the program and follow the instructions that appear on the screen to download the Windows 10 installation files and create the related DVD or USB media.
Step 2. Back up all your personal files
When you format your computer and then reinstall Windows, all the information it contains is erased. Make sure you've backed up any files you want to keep using a backup tool, such as an external hard drive or clouding service. Any software or programs that you normally use will need to be reinstalled at the end of the procedure.
See this article for more information on how to back up your data
Step 3. Boot the system using the installation disc or USB media
Once you've backed up all your personal information, you'll be ready to proceed with formatting your computer's hard drive and then reinstalling the operating system. To do this, you need to boot the system using the newly created USB disk or media instead of from the internal hard drive as is normally the case. You need to configure your computer to boot by reading the information contained on the installation disc or USB media created in the previous step. The setup procedure varies depending on the version of Windows installed. Systems running Windows 7 or earlier use the old BIOS firmware, while more modern systems running Windows 8 or later use the new UEFI firmware.
- Windows 7 or earlier (BIOS firmware): Reboot the system, then repeatedly press the function key to enter the computer's BIOS. The key to press is superimposed on the startup screen of the computer, before the operating system begins to load. Normally, you will need to press one of the following keys: F2, F10, F11 or Del. Enter the BIOS "BOOT" or "Boot" menu, then choose the "DVD" or "USB" option to configure the primary boot device.
- Windows 8 or later (UEFI firmware): Go to the "Start" menu, then select the "Shutdown Options" button with the right mouse button. Hold down the ⇧ Shift key while selecting the "Reboot System" option. From the menu that appeared, choose the "Troubleshooting" item, then select the "Advanced" option. At this point choose the option "UEFI Firmware Settings". The "Boot" section of the menu that appears allows you to change the order of your computer's boot devices, allowing you to choose between DVD or USB drives.
Step 4. Let's start the installation process
When prompted, press any key on your keyboard to load the Windows installer and setup program. Uploading all the files required for this operation may take several minutes.
Step 5. Choose your language options
Before the actual installation begins, you will be prompted to select the system language settings. When finished, to start the installation process, press the "Install Windows" button.
Step 6. Enter the Product Key you have
When installing Windows 8 or later, you will be prompted to provide the relevant Product Key immediately. By installing Windows 7, however, you will have to enter this information only at the end of the installation procedure. If you intend to enter this information later, you can skip this step.
Step 7. Choose the "Custom" installation option
This step allows you to delete all data currently on your computer and proceed with a "clean" installation of the operating system.
Step 8. Choose the hard drive or partition that contains the current Windows installation
This drive is indicated in the list as "Primary" and usually also has the version of Windows in use.
Step 9. Press the "Drive Options (Advanced)" button, then choose the "Delete" item
In this way the selected partition will be deleted and all existing data will be removed. Upon completion, the volume in question will be labeled "Unallocated Space".
- You can repeat this step for all the partitions you want to delete and reunify into one main volume. Obviously, any data on those partitions will be deleted. To merge multiple blocks of unallocated space into one partition, press the "Extend" button.
- If you wish, you can split an existing partition into multiple partitions. This step can help you organize your files better. Select a unit of unallocated space, then press the "New" button. This way you will proceed to create a new partition. Make sure the partition you plan to install Windows on is at least 20GB in size.
Step 10. Select the drive on which you want to install the operating system, then press the "Next" button
At this point, the actual Windows installation process will begin. Copying the necessary files and configuring the installation takes approximately 20 minutes.
Step 11. Create your user account
Once the files have been copied, you will be prompted to create a user account. This profile will also have system administrator privileges. You will also be asked to name the computer. This is the name by which the system will be identified when connected to a network.
Step 12. Enter the Product Key (for Windows 7 systems only)
If you are installing Windows 7, at this point, you will be asked to enter the product key. You can skip this step if you intend to enter that information later.
Step 13. Choose the configuration settings of the "Windows Update" service
Most users should choose the "Recommended" option to ensure that the system is automatically updated to ensure the highest level of security.
Step 14. Set the time and date
The system should be able to automatically configure this information, but you may need to make some changes.
Step 15. Identify the type of network you want to connect to
Choose the best network settings for the infrastructure your computer is connected to. This step impacts the network security level and data sharing settings.
Step 16. Start using Windows
After choosing the type of network connection, you will be directed to the Windows desktop. If you did not enter the product key in the previous steps, you will be prompted to do so now.
Method 2 of 2: Mac OS X
Step 1. Back up all your personal data
When you decide to reinstall the OS X operating system, all the files on your Mac will be deleted. Make sure to back up all documents, images, videos, and all other personal data, and save them in a safe place, such as an external hard drive or cloud service. See this article for more information on how to back up your data.
Step 2. Restart your computer, then, after hearing the characteristic sound of the boot sequence, hold down the keys
⌘ Command + R. Release them as soon as the Apple logo appears on the screen.
Step 3. Choose the Wi-Fi network you want to connect to
You may need to choose the network to connect to. If you don't have a Wi-Fi connection, you'll need to opt for a wired connection using a network cable. In order to proceed with the reinstallation of the OS X operating system, you necessarily need an internet connection.
You can also select the Wi-Fi icon in the upper right corner of the screen and then choose the network to use
Step 4. Choose the "Disk Utility" option from the "Recovery" menu
A new window will appear listing all the storage drives on your computer.
Step 5. Choose your Mac hard drive, then hit the "Erase" button
You can leave the default configuration settings that appeared unchanged, just give the drive the name you want. Press the "Initialize" button to confirm your action. After the initialization process is complete, close the "Disk Utility" window to return to the "Recovery" menu.
Step 6. Choose the "Reinstall OS X" option, then hit the "Continue" button
The OS X installation procedure window will appear. A message will also inform you that the status of your Mac will be checked directly from the Apple servers.
Step 7. Read and accept the terms of the license agreement
In order to proceed with the installation, you will have to accept the terms of the agreement that is offered to you by Apple.
Step 8. Choose the storage drive on which to install the new copy of OS X
Select the same volume that you initialized using the "Disk Utility" program.
Step 9. Enter your Apple ID
You will be asked to provide this information to verify that you have a valid license to install and use the operating system.
Step 10. Wait for the necessary files to download
The installation procedure will download all the files needed to install OS X on your Mac. The time required to complete this step depends on the speed of your internet connection.
Step 11. Choose the region and keyboard layout for your language
The options selected by default should already be correct.
Step 12. Connect to the network
Choose your Wi-Fi network, then enter the password to be able to establish a secure connection. If you are connected via a network cable, this step will be omitted.
Step 13. Choose how to restore your information
You can do this by using a "Time Machine" backup or by transferring them from a Windows computer. Regardless of your choice, follow the on-screen instructions to perform data transfer and recovery. If you want to create a "clean" installation, choose the option not to transfer any previous information.
Step 14. Log in to your Apple ID
This step grants access to the Mac Store and your iTunes purchases.
Step 15. Create a user account
By default, OS X will use your Apple ID as a user account to log into the computer. If that doesn't suit you, you can choose to create a local user account.
Step 16. Complete the setup process
You will be guided through a few more minor steps to complete the setup before you can log into your new desktop.
