An old computer can hold far more than the documents visible on its desktop. Browser sessions, downloaded statements, saved email, application data and additional user accounts may remain. Dragging a few folders to the trash is not a reliable way to prepare the device for another owner.
Do not erase the only working copy
First decide what must be preserved. Include files stored outside the obvious documents folder, local email archives, application-specific projects and any information needed to continue using licensed software. If the computer belongs to an employer or contains organizational records, follow its return and retention process rather than erasing it on your own initiative.
Make the appropriate backup or transfer, then open a selection of important files from the destination. Check that whole folders arrived and that the applications can read them. A completed progress bar is less reassuring than a verified copy. Keep any encryption recovery information needed to access your retained data in a secure place separate from the device being transferred.
Use the process intended for your system
Consult the operating-system manufacturer's current instructions for preparing a device for sale, donation or recycling. Sign out or deauthorize accounts and services where those instructions require it, and address any activation or ownership lock through the normal account process. Do not give the next owner your password as a shortcut to making the computer usable.
Choose an erase or reset option that removes personal content, not one designed to keep files while repairing the system. In Windows, for example, Microsoft distinguishes Keep my files from Remove everything and describes a Clean data option for consumer transfers. Read the choices carefully because similarly named recovery processes can have different purposes.
Check every installed storage device covered by the transfer. A reset aimed at the system drive may not address an additional internal drive or a removable card. Disconnect backup drives that should remain yours before beginning, and verify the target of any destructive operation. If the computer's storage layout is unclear, obtain help rather than guessing which drive a command will erase.
Match the assurance to the sensitivity
Consumer reset guidance should not be presented as a guarantee that every possible recovery method has been defeated. Microsoft states that its consumer data-erasure functionality does not meet government and industry erasure standards. Equipment holding sensitive business, regulated or otherwise high-consequence information needs a sanitization process appropriate to that responsibility, potentially through an authorized service.
A computer that no longer starts still may contain readable storage. Do not put it into a donation pile because you cannot reach the desktop. Ask an appropriate repair, IT or destruction provider how the data will be handled, and obtain any documentation your organization requires. Avoid improvised physical destruction, which can create injury and battery hazards without providing a trustworthy record of what was sanitized.
After the approved process finishes, confirm the expected setup state without signing back into personal accounts. Remove memory cards, external drives and accessories that are not part of the transfer. Arrange reuse or electronics recycling through a suitable recipient. The point at which the computer leaves your possession should come after the data decision, not before it.
