The PC has been sitting in my attic since then, and I am now confident that I don't need anything from it so can dispose of it. Wait, though! There's data on that hard drive belonging to the university that might be of use to an enemy!
I tried to remove the hard drive, but couldn't get at one of the screws as it was behind the power supply, which itself wouldn't come out because I couldn't actually find its screws. Gawd knows how it was manufactured. I tried to take the casing off my hard drive but didn't have a star key spanner head small enough.
How, then, could I destroy the data?
It was then that I saw the little sign on the hard drive saying "Fragile".
Here's the result. Multiple hammer blows plus two from a sledgehammer that buckled the housing.
I have to say, it was very satisfying. If anyone succeeds in opening up that casing now, they'll find 0s and 1s falling out everywhere like glitter.