Computer crashes??

Newish computer, about 5 months old. Im having problems with it and I can't figure out why. When im doing a task, somtimes randomly my computer will make a strange squeeky type of sound from the speakers, the mouse will go unresponsive and then the screen will turn blank. This leaves me to have to hold and press the button on the cpu to turn it off.
Does anyone know why this is happening and what I can do to stop it?
I have a feeling its something to do with the fact that the graphics are shared onboard.
Thanks

 

I would look at a bad memory chip, due to shared memory for the graphics card would have nothing to do with it. What is the manufacturer of the computer?

 

Mesh computers. I recently rang technical support and they sent me some drivers. Update them and so far its been working fine. I hope that there isn't a problem with the memory :S