Final answer:
Lisa needs a CD player or portable electronic device connected to speakers to hear music and game sounds on her computer.
Step-by-step explanation:
The device that Lisa needs to attach to her computer in order to hear music and the sounds of a computer game is a CD player or portable electronic device connected to speakers.
These devices can play rock or rap music CDs or mp3 files.
Additionally, Lisa may need a lightweight table to place the CD player or portable electronic device on while using her computer.