Technical issue..

[Elcostoh]

Hi, I dont know if I should ask here. But I have a problem. I use an hp prodesk g3 sff and I wanted to add another hdd, but there is only on sata cable going from the motherboard (6pin) to the hdd. So I took another cable from an older hp sff pc which have 3 sata ports but works with a 4pin on the mobo. But I still put that 4pin on the 6pin port on my g3, but once I turned it on the start switch light shut down immediately. I tried again and again by removing the power cable and putting it again, but nothing. Then I put back the other 6pin sata in the port and connect it to the hdd, but there is some smoke that goes out from that hard disk once I put the power cable without even pressing the start switch, I removed the cable immediately and I dont know what to do now. I changed the hard disk but the pc dont start, nor even the start switch light. Any advices ? Can my pc be functionnal again ? If so, what should I do ? (Sorry for my bad english)