Heat! Heat may be your problem. I have been repairing coputers for 38 years of various types. I find that it is quite common for laptops to accumulate
debris inside that blocks adequate airflow. Download and install this free utility "Coretemp. http://www.alcpu.com/CoreTemp/ You can use it to see if your CPU is getting too hot and take action appropriately. A short article on the subjetc can be viewed at http://www.bestpcfixit.com/forum/laptop-freezes .

Hi. I am having a similar issue. But my laptop only freezes randomly when I am connected to a wireless network. I have used my laptop for longer periods with cable internet and I didnt have any problems. As soon as I connected to the wireless it starts to freeze randomly especially if watching videos. I repeat I dont have these sort of problems if I am connected with the cable. I would be very thankful if you can help me with this