I ordered a new CPU cooler and I went to install it, I took the cpu out and cleaned off the old thermal paste with alcohol and put it back in and was going to put the new cpu cooler on but realized i didn't have the correct bracket i needed so i just put my old cooler back on and everything back the way it was and now nothing happens when i hit the power button. Nothing comes on at all. Does a cpu failure keep the pc from turning on at all? Or is it possibly something else I screwed up?