Well, you could just turn everything unneccesary off. That is, if people in Michigan ever turn off their furnaces....?
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From the experiments of me and a couple other people, just adding a bit of any sound absoring-material isn't going to work. Put the computer on a roll-around cart, get long mic cables, do your actual recording in the best-sounding room you have, and during actual recording, wheel the computer cart into another room (-or, just going around a corner with it helps too).