|No it doesn't start smoking or anything like that it just turns off but the power led's on the motherboard remain on.|
the harddrive is the only thing connected to that data cable and i run it on its on power cable as well, i've tried starting it without the data cable attached and when i press the power button everything lights up like it should do then turns off a split second later.
I have also tried diffrent power conectors and the problem is the same.
I'm well aware that you shouldn't connect anything to the power supply once you have turned it on when i managed to get it to start without the harddrive connected i then connected it after and it turned off knowing that you shouldn't that i only did it once just to be absolutely sure thats what was causing the problem.
One other thing i forgot to mention which i'm sure is related to the power supply my dvd drive is now dead also, i installed that the same time i installed the first new harddrive, also attached to its own power cable and data cable.