Here's the link to the service manual. That should contain everything you need to remove the cpu, apply AS5, and reinstall it. Also double check that all of your fans are working and spinning properly. You should be able to feel warm air venting from them. It's possible one of them would need to be replaced.
edit: also check your cpu fan. I think you should be able to check it's rpm in the bios. Make sure that's working properly as well.