Memory being unseated is a common problem with no display on the monitor. Try reseating the memory (test one at a time if possible).
Next, reset the CMOS again, remove the discrete video card so that On-board video is the default again, plug cable into Onboard instead of video card, make sure solid connection exists between CPU-heatsink (apply more thermal paste IF you have any otherwise do not dare remove the Heatsink from the CPU).
What was the leftover packaging, how much was it and did it have physical damage (burn marks, etc...) and did it smell then when you tried turning the computer on. Depending on the circumstances and if the motherboard supports instantaneous shutdown due to processor overheating, that is why the whole system shut down.
Slmclarengt
Put your hand on a stove for a minute and it seems like an hour. Sit with that special girl for an hour and it seems like a minute. That's relativity. -Einstein
Website: WWW.BnDClan.COM