one of a few industrial sound-proof materials that i know;
1. ear plugs
2. head phones
3. pop-corn (somebody told me it works)
4. a louder-than-cd-drive audio tracks
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one way is to put your computer case on the floor so it won't be ear-level anymore. the advice on better cd or dvd drive is very sound. there are some brands that have very quiet drives. asus, lite-on for example.