Components were melted? That's not good at all. You may have more issues than just a power supply. The fact that there were burn marks on the unit and melted components might mean that your motherboard is in serious condition and might need to be replaced.
Also, double check all of the connections. Sometimes, when installing new hardware, the connections aren't in secure enough. Unplug all of them and them plug them back in. Hopefully the former is not the case. Best of luck.
_________________________
It's most likely a problem with your flux capacitor.