Solution 1:

Some laptops are known to cause trouble when they are used with linux. If you could provide more information about your computer (manufacturer, model, BIOS version) it would be very helpful to find a solution for your problem.

Solution 2:

Check your CPU is clocked down when not in use. eg. right click a GNOME panel, ‘add to panel’, ‘CPU frequency scaling monitor’. It should go down when you're not doing much. If it's always on top speed you've got a cpufreq problem (sometimes a BIOS upgrade helps fix this).