Does your AMD coolerhave 2 or 4 spring loaded screws?
What is the manufacturer and model number of your cooler?
If the tip of a spring-loaded screw does not reach the tapped hole in the CPU base plate, slacken off all the otherscrews until none of them are engaged in the CPU baseplate.
Press down on the first spring loaded screw. Engage the tip in the tapped hole on the base plate. Rotate the screw through one or two turns, sufficient to engage the thread. Do NOT tighten down the first screw any further. Doing so may prevent any more screws from engaging in the base plate.
Move over to the next screw (on the diagonally opposite corner for 4-hole fixing). Press the tip of the second spring loaded screw down and engage the thread in the base plate. Rotate the second screw through one or two turns, sufficient to engage the thread. Do NOT tighten the second screw down any further.
Repeat for any remaining fixings, until all the cooler screw tips are engaged in the CPU base plate.
Rotate the first screw two more turns. Do NOT fully tighten yet. Move to the diagonally opposite coner and tighten the next screw by two turns. Repeat until all screws have received two turns.
Move back to the first screw. Apply two more turns. Repeat for all remaining screws.
Continue to tighten all screws a couple of turns each time, until all screws are tight.
The idea is to slowly compress the heatsink down on to the CPU, in much the same way you would torque down a cyclinder head on an engine.
If you tighten the first screw fully before engaging all the others, the heatsink will tip over on one side, leaving the other screws high above the base plate, with no chance of engaging their threads.
Good quality coolers are easy to mount. Badly designed coolers are very difficult or almost impossible to mount. Yours may be one of them. Take care not to gouge the mobo if your screw driver slips. Good luck.