Not a PC but...
We did the testing for optical transceivers in a seperate building and every so often they'd all start to fail at once. Wasn't a problem when they were tested in the main cleanroom. The culprit? Mobile phones, you'd be able to tell someone was about to receive a text message as the failures were almost exactly 20 seconds before someone got a message. Wasn't an issue in the cleanroom as mobile phones were banned within the testing area due to the sensitivity of the equipment. I recall one piece of kit in there had a 1 metre taped area around it and a big warning sign not to cross the taped line if you had a pace-maker
Biting the hand that feeds IT
