Silent cpu chassis

You can use a zalman "fan mate" series rpm adjuster, which costs about $7 for a single fan, or get a 5.25 inch multiple fan controller. Newegg had one brand for around $12 plus shipping. Or if you have a big case with multiple fans, try disconnecting one. For video cards, you can get a low end fanless one or buy a copper heatsink. On many newer boards, you can enter the "hardware monitor" or "pc health" sections of the bios and lower the cpu fan there.