2026 Version
Perhaps you have an old work computer. Or someone has given you an old computer. You want to wipe everything off of it and start over. This is how.

Before You Begin
You will need the following:

• One or two USB sticks. 16Gb or larger.
• Another computer.
• Possibly Hiren's BootCD PE and Rufus
• Possibly hard drive drivers for your computer. They can be downloaded from the manufacture's website. Save them to one of the USB drives.
• Installation Media for Windows and any other programs you will want after installation

Dell Inspiron series computers are designed for business use. They have security features to prevent unauthorized users from accessing your information. The only way to completely erase the data and any software already installed is to wipe the hard drive. That is going to be the first step.
You need to access the BIOS settings and then use the Secure Wipe to wipe the hard drive. This will take about two hours. Here are the instructions from Dell. https://www.dell.com/support/kbdoc/en-ca/000146892/dell-data-wipe.
If you don't have a Dell, or the computer doesn't have a built in wipe, you will need to use Hiren's BootCD to wipe the hard drive.