Blown power supply
Ok, this might be a weird issue, but here it goes. My power supply recently had a catastrophic failure (sparks everywhere, plastic burning smell, etc). This kind of sucks, but its still under warranty and all the other components of my pc seem to be working fine. The problem is, is that after attaching another power supply and running the pc for a minute or so, I notice the plastic burning smell again. I don't know if this is just residual, or if it is a sign of more extensive damage. If anyone has any input on this it would be greatly appreciated. I just need to know if its safe to continue to use my components without further damage.
I would remove the second power supply and find someone with a PSU tester which can measure voltages and supply a load on 3.3V, 5V & 12V lines and test the psu to see if it is ok at light test load. (there should be no burning smell and all voltages should be correct)
I saw a u-tube video of a computer PSU catching fire. (posted by Benjamin Burrows of UBCD4Win fame)
It was a faulty motherboard destroying the power supply and several old PSU's were destroyed for fun.
So it is difficult to know if motherboard or PSU is the problem now.
Remove your Hard Disks (valuable data), leave only one memory DIMM (if you have several),
If you have a Graphics card and integrated graphics remove the graphics card before trying again.
Was the second PSU of appropriate power rating ? (at least as high as the previous one)