I received a computer for repair today, the complaint was that the computer would not power on; this computer was 
definitely memorable. After unpacking the computer, I noticed one of the filler plates was missing from the back of the computer; my first thought was that it wasn’t the level of work I expect from my technicians and my second thought was that it isn’t good for the computer’s internal air flow for that filler plate to be missing. Then I opened the case…
Inside the case I found mouse droppings on the power supply and scattered around the motherboard. After taking a closer look, I could see trails of mouse urine which had eaten through the copper traces on the mother board. That would explain why the computer will not power on. Unfortunately, the damage caused by the mouse rendered this computer unrepairable.
I hate that we lost a computer to damage that was easily preventable; if the previous technician had taken the time to prepare this computer properly, that filler plate would not have been missing and the mouse would have never gotten inside to damage the computer.