The short answer
Back up, sign out of everything, deauthorise licensed software, then erase the drive properly. Deleting files and emptying the bin does not remove anything.
- Back up everything you want to keep, and check the backup opens on another machine.
- Sign out of accounts and turn off any device-locking feature, which otherwise leaves the machine unusable for the next owner.
- Deauthorise licensed software that has a device limit.
- Use the built-in secure reset. Reset this PC with the "remove everything and clean the drive" option on Windows, or Erase All Content and Settings on a Mac.
- Recycle it properly at a council centre or a retailer take-back scheme. Never in the household bin.
What will ruin it
A drive that has been formatted normally still contains recoverable data. If the machine held anything genuinely sensitive and you cannot run a secure erase, physically destroying the drive is the only certain answer.
Why it works
Deleting a file removes the index entry, not the contents, which stay on the disk until overwritten. Secure erase and modern encryption both work by making that remaining data unreadable rather than by scrubbing every sector.
Tipking is general household information, not professional advice. Test anything on a hidden patch first. Full disclaimer.
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