Tucked away in a corner of Frostytech is a collection of acoustical absorbing / barrier / sealing & vibration damping materials, originally provided as a material sampler some years ago by the company Polymer Technologies. If you want to sound proof your computer a little more extensively than melamine foam can offer, this is a good primer on what different material technologies are commercially available.
Any major computer upgrade generally requires a full software reinstall too. No so if you heed the advice in the guide to Upgrading a Motherboard without Reinstalling. PCSTATS Tips