How to fix a bad case rattle

The point is to remove heat from the case so:

1. heat rises, so fans at the top of the case blow the hot air out and fans at the bottom blow cold air in.

2. fans near hot components (CPU, Power supply, high end graphic cards) blow air out because you want to remove the hot air - not spread it around.

3. you have to have good airflow where hot air is continually removed and replaced with cool air - so, fans at one side (usually the front) blow air in while fans on the other side (back) blow air out.

I had this after disassembling to replace the hdd. In my case it turned out to be the flat cable that comes from the power button and goes around, passing near the right speaker. It's somewhat loose (that's normal) and it was vibrating to the speaker. I basically opened it up again, poked that cable, closed back again and the rattling was gone.

You can do it by following this video up to detaching the palmrest (1:12)