I bought a desktop PC last year of Gumtree for $40. The owners gave it to me with a fresh install of windows on it.
Out of interest, I ran on it and and recovered all their old files, including nude pictures I then securely deleted the recovered files. The reason i did it was because I was also curious about what was on there for when I dispose of old computers and what people could recover. It was an interesting exercise and made me realise that realistically I wouldnt sell a computer unless I had removed and destroyed the drive.
This might be of interest:
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