My computer is unable to start, moreover is very strange

My computer CPU is P4 1.6G, other did not say, used also to have 6~7 years, from started to move a while ago period of time to halt, was the picture decides in there, the mouse keyboard has not reflected.
Now develops starting “the drop” one will be from now on the power source lamp and the hard disk lamp has been shining, the monitor also demonstrates does not have the signal, but the CPU ventilator and the power source ventilator is actually revolution ~ I thought that was the power source has gone bad, has traded Great Wall P4 power source 300W, normal two days have not been good the ~ little brother to kneel in here ask the fellow masters to help ~ extremely to thank!
Possibly is the hardware becomes less crowded or is the dust are excessively many
Processing method:Turns on the engine case the hard disk, things and so on memory tears off looks up again, sent the dust to clean up should be possible
Hoped that has the help to you.:) Where bad contact should be, my family is monitor that big plug
You call the computer shop the human will help you (also to be possible) to take in certificate of deposit that contact the place to use under the eraser Will not be poisoned, in this year this kind of virus not will also see, must see is the large-scale eruption