Hi any one help.. the problem with the compaq presario c300 is when i try to start it up the only response i get is the lights on lap top flash rapidly.this is the lights on the front as well as the lights on the start. cheers ross

The flash or blink codes you can log on to this site http://h10025.www1.hp.com/ewfrf/wc/document?lc=en&dlc=en&cc=us&lang=en&product=3213867&docname=c01732674
and reference the blink codes. this is also the c300s service manual so you can go back and forth on other things. but if your swapping the motherboards then my suspect is your power supply. make sure that the C300 is getting 18.5 or slightly above if your on a digital meter. but if its below then it wont have enough power to turn on. speaking of power it could be the jack, the pigtails to the motherboard or a loose connector on the wall male end. so make sure to check your path of power from the wall to the unit. and follow electric guidelines and dont shock yourself. but what I used is a paper clip to put into the male end of the Dc voltand the inside is positive and set your ohm meter to DC 20 and it should read 18.5 v.

Got a compaq presario c300, when i power it up the lights flash for a few seconds i hear the fan kick in for a short time then it goes off, i bought a second laptop for spares as i needed the lcd screen, tried swapping different bits inc motherboard but got exactly the same problem, can anyone help ?