There are a couple of things that can go wrong with it. The most common thing on laptops is overheating.
You will know if your laptop is overheating if it happens one ore more of the following:
-The keyboard and the bottom of your laptop are very hot when the laptop is working.
-The CPU fans are working all the time at maximum rotation speed and operate much louder than before.
-The laptop suddenly shuts down by itself without warning. When it just started, the laptop was shutting down after 1-2 hours and how it shuts down after 5-10 minutes of operation.
-The laptop works fine when it runs idle, but shuts down as soon as you start using any memory demanding applications (DVD player, image editing software, video editing software, etc.).
Follow this steps to avoid overheating:
-Don't use your laptop in full sunlight for extended periods
-Don't leave the laptop in a closed car on a sunny day
-Don't place the laptop on or near extreme heat sources, such as radiators, hot air vents
-Turn off your laptop before putting it in your carry bag
-Turn off your laptop when not in use for a long period
-Work on an even surface as much as possible, not on your lap!
-Clean the air vents in your laptop regularly by using a can of compressed air
-Get more space under your computer by propping it up on something when it's on a desk
-Consider purchasing a laptop cooling pad
-Consider purchasing an external fan
To clean your laptop's cooling system:
-Shut down the laptop ie do not leave it suspended, sleeping or hibernating.
-Unplug all cables from the unit and remove the battery pack
-Get a can of compressed air and blow it into all vents around your computer - this should clear out any dust and hair.
-Do Not use a vacuum cleaner
If it is not overheating, then it is a hardware failure. Could be the RAM memory, processor or the motherboard. You can test the RAM with this program: http://hcidesign.com/memtest/MemTest.zip
If RAM is ok, then only replacing hardware equipment could corner the problem.