Have you sold or gotten rid of an old computer before? Did you clean all your data out of it?
I often see people getting rid of their old equipment thinking it’s wiped clean but its not.
so what happens to that computer you threw out?
some go to be crushed and recycled, others get sold at OP shops (like at the tip) for dirt cheap. So there for, someone will have your old computer and could potentially retrieve old data! Yes Everything! Even though you have formatted your hard drive it is still recoverable with potential software.
To put it in a simple term, imagine your hard drive as a hotel. You have a reception and rooms. The reception tells you what rooms are available and what rooms are not. The rooms is were all your data is stored, (please note that your operating system has a long term lease in room 1).So when you delete something (leave the room) the reception will know about it and now the room is vacant to be used again, although all your belongings are left behind, if someone new moves into that room then all your belongings will be lost.
so by formatting your hard drive all youre telling the reception is that all the rooms are free. But the data recorded as 1’s and 0’s on the disk are still there (personal belongings) .
With special software you can eliminate the reception all together and scan the rooms to see what you can find, pictures, documents, tax file numbers your addrees, passwords etc. so sometimes its worth doing properly and making sure you didn’t leave anything behind.
There is software available on the net to properly delete a hard drive by rewriting every sector (the cleaning lady) for example having data “0110 0010 1100 1100” the software will rewrite that to “0000 0000 0000 0000” there for it will be impossible for someone to retrieve the information that was there previously.
I hope this gives you some understanding when disposing an old computer and may protect someone’s privacy one day.