computer igloo

I want to put together a wooden cabinet of some sort to house my computer so that when I record it'll be much quieter than it is now. Can you recommend something I can put on the floor of the thing to seat the computer on so that the vibration of the machine won't communicate itself to the cabinet?

Sounds like you might wanna search this forum for a thing called a "riser" (or drum riser) To decouple it from the floor. in short you need: mass with demping material underneath. you might actually wanna raise that whole structure with 4 carriers. Furthermore you could build some mass structure around your computer but keep the back (partially) open for the fan to blow out hot air. if your pc also has a fan seated at the front, leave an opening in the box there too. Altho it will expose air and therefor sound, you need to keep your pc cooled.