No sound coming out of your laptop is usually caused by a broken headphone socket.
Inside the headphone socket is a switch which prevents sound from being sent to the speakers when a set of headphones are plugged into the laptop. This can break if the headphone cable has been tripped over and the worst case scenario is that the headphone socket itself has broken completely and detatched from the motherboard. Wiggling the headphone jack into certain positions may resume audio playback confirming a break.
Replacing the headphone socket involves stripping the laptop down completely to motherboard level. We charge a flat price for £60 to replace a headphone socket.
Another cause of sound failure is a driver issue or windows audio filter corruption. A symptom of this is no sound output at all from the built in speakers or headphones and either no speaker icon or a crossed out speaker icon in the bottom right area of windows.