Back up any files you want to keep
Sign out of accounts and deactivate software licenses
Create a bootable USB with a trusted OS installer or wipe tool
Boot the PC from the USB
Delete all partitions on every connected drive
Recreate partitions only if you plan to reinstall the operating system
Perform a full format or secure erase on the drive
Use manufacturer secure-erase tools for SSDs if available
Remove additional internal and external storage devices if needed
Reinstall the operating system from trusted media
Change firmware passwords and reset BIOS or UEFI settings if needed
Clear TPM and secure boot keys if you are repurposing the PC
Verify the drives are empty before handing over or disposing of the PC