Recommended reading for anyone new to Athlon HSF installation. Doing this wrong can result in cracking your Athlon's die (i.e. the important bit), though it sounds like you're being careful enough to not run into that problem.
To get an idea (read the document linked above, this is just an overview and I could have omitted something important) generally this is how it goes:
- Note that exactly
ZERO of these steps involve pushing down on the HSF itself. See statement about die-cracking above.
- Orient it so that the cutout on the HSF lines up with the "Socket 462" heading on the socket
- Tilt the HSF
slightly to get the clip on the other side (the one without the slotted extension) under the mounting hook on the socket. No pressure should be involved in doing this, the clip should just slide under
- Lay it down on top of the CPU, making sure it's straight and that the HSF doesn't come into contact with the socket.
- Use a flat-head screwdriver or similar tool to press the other side of the clip (the one with the slot extension; do NOT do this with a screwdriver unless the slot's there or you'll probably kill your mainboard, and use a size that won't slip out of the slot) onto its hook.
- Double-check everything to make sure it's lined up and securely attached. The die should come into contact with the thermal pad, the heatsink should be in contact with all four spacers, and the heatsink should not come into contact with the socket. The heatsink should be parallel to the CPU.