Spudley: "In any competent IT department, if a computer is returned for whatever reason (employee leaves, gets an upgrade, etc), the first thing the IT department should do is wipe the disk and re-install the OS."
Nope. The first thing they should do is take an image of the disk. Then wipe and reinstall.
The backed up image saved a lot of problems at one company when HMRC came sniffing after some suspicious financial activity. It turns out the former CFO and CEO had been misusing funds and the backups provided evidence of their culpability, meaning HMRC went after them personally rather than the company itself.