Embodiments of a portable computer, a woofer speaker mounting structure for a portable computer and methods thereof can reduce transmission of vibrations from speaker to remaining portions of the portable computers. A woofer speaker mounting structure for a portable computer can include a case, a woofer speaker for producing bass sound positioned on the case and formed with support pieces, dampers for absorbing vibration from the woofer speaker can fit into the support pieces and can be coupled to the case. The damper can include a damper body made of an elastic material and through which a central hole is bored and shock-absorbing portions. Due to the structural and material properties of the damper, vibrations are also absorbed. Therefore, the operational characteristics of a portable computer are improved.