Computer dead no power

This morning i have a computer in Warwick with no power getting to the machine. After checking the fuses (by the way its almost never the fuses or the power switch) and the mains , We putΒ  a new power supply unit in to the machine and tested it , This was all that was needed on this machine but a simular set of faults are apparent when the motherboard, processor or memory simm boards have a fault.

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