Re: Probably my first diagnosis in anything resembling tech support was something similar.
One of my previous tower PCs had a power switch right on the top of the front panel itself. The manufacturer had carefully designed the top of the panel so that it was slightly lower than the top of the PC case itself. This meant that placing anything on top of the PC wouldn't accidentally depress the power switch.
Of course, they never factored in cats jumping on top of the PC and switching it off!