Apologies if this has been asked before, I couldn't find it on a quick search but I am sure it can't be a new query.
I bought a 2nd hand computer some time ago and now am about to give it to my niece for her studies. However just recently with the recent news frenzy it brought another thought to mind.
My query is, short of reformatting the whole hard disk, what actions could I take to ensure there are no residual tracks of the previous owner on the computer?
With this frenzy about Child Porn I would hate for the embarassment should she ever take it for repair and such tracks were evident.
As matter of course I have deleted, the normal things like temp files, cookies, autocomplete and defragged but I understand subtle "records" are kept in a swap file or something???? or index.dats?????
Also its a big hard disk with little used, does defragging actually clear any chance of retrieving a previously deleted porn pic????
Any help and advice appreciated

I bought a 2nd hand computer some time ago and now am about to give it to my niece for her studies. However just recently with the recent news frenzy it brought another thought to mind.
My query is, short of reformatting the whole hard disk, what actions could I take to ensure there are no residual tracks of the previous owner on the computer?
With this frenzy about Child Porn I would hate for the embarassment should she ever take it for repair and such tracks were evident.
As matter of course I have deleted, the normal things like temp files, cookies, autocomplete and defragged but I understand subtle "records" are kept in a swap file or something???? or index.dats?????
Also its a big hard disk with little used, does defragging actually clear any chance of retrieving a previously deleted porn pic????
Any help and advice appreciated