Then you probably still may not have the HSF fan on correctly. Too much thermal compound is as bad as too little.
What you're telling is that when you hook up the CPU power, ("the 4 pin"), the system quits. If it's not a problem with the HSF, then you've damaged the board, CPU, PSU, or all three.
My original statement "you have no business putting pour hands inside a computer", while you don't agree with it, is nonetheless factual.
Less than one percent of shipped electronics parts are defective when shipped. Yet, (I think) more than 5% are returned as "defective".
People returning things as "defective", make prices go up, not to mention causing the rest of us to wade through pages and pages of their of their bogus, "reviews" at Newegg. It seems that everybody that can't get something to work also has "high technical ability". I tend to equate "very high technical ability" with a "massively inflated ego", and nothing more.
Now, as harsh as my comments may seem, I really do want your computer to work. I think you haven't "rehearsed" or researched enough before trying to do this task, and you're paying the price.
I further believe that you need more help than you can hope to receive this, or any other forum. There are certain skills involved with the assembly of electronics equipment, and they're not instinctive, they need to be learned. Most of us tend to take this for granted, since we've built many machines. I've made fatal mistakes in servicing my computers, but that said, I also know when I've made them, and that goes a long way toward not repeating them. So, someone who doesn't know that they've made a mistake in the first place, is in deep caca, IMO.
A friend that can give you hands on assistance, might prove to be your salvation.
That said, I'm sure everybody here will continue to assist you in any way we can.