Is there a way to stream all audio from PC to Android via USB? My headphones socket on my laptop is busted, and I'm wondering if I can stream all the audio (every sound the PC makes) from my laptop to my Android, so I can use the headphones connected to the phone. 

It has to be by USB/Firewire, as my laptop doesn't have Bluetooth...
You would better off getting a pair of USB headphones than streaming it to your phone.