Random crashes on a Netware server (1-3-ish times a week) = dishwasher in the kitchen, which was immediately behind the server. Fix: Move the server (which was just on a table) to another corner of the computer room.

Regular increase in coax Ethernet network error rate = moon tides affecting nearby river and increased ground water during heavy rain affecting ground voltage level on side of building next to the river.

Poor or unable-to-connect modem link = nail through telephone cable on wall.

Misbehaving fibre optic token ring topology; 'data getting corrupted in transit' = EMP being injected into one electrical/optical transceiver on one network card in a PC closest to 'The largest laser in Europe' (and its power supply). This was at a UK Government defence research lab in the 1990s.

200MB hard disk in PC - would spin down when the case screws were inserted. Never did find the root cause (pressure on 'something'). This was my work PC so I just left off the screws.

Computer room overheats = Delivery of listing paper put on floor in front of self-contained circulating air cooling system in the corner of the computer room. Fix: Move the boxes.