My headphones and speakers work properly on other devices so does that mean that the on board sound is dead, is there any tests or something that can be done to make sure?
Try using an Ubuntu Linux LiveCD. That has a self contained audio stack which should work with most Realtek onboard audio devices. If it doesn't work in that, it will need to be replaced
EDIT: Just as a side note, since onboard audio devices often do not have their own oscillator they use a system clock for reference. If you overclock any of the system busses (such as the base clock in Intel systems) you can render the Integrated audio non-functional.