Laptop Shuts Down on its own

Laptop computers combine the power of a personal computer with the flexibility of a mobile device.
They are excellent tools for businesspeople and students, providing access to relevant materials on the go.
When laptops shut down without being prompted, this typically indicates that the unit is overheating, has a malfunctioning battery or requires a software or BIOS update.
While isolating the problem can be time-consuming, correcting the problem is simple.
Check for BIOS updates on the laptop manufacturer's website.
Check for operating-system updates.
Make sure that there aren't any obstructions to the air vents.
These will cause overheating and make the laptop shut down.
Remove the laptop battery, open all hatches and blow out any areas you have access to with compressed air.
This should dislodge any obstructions.
Retrain the battery, which may have lost its ability to hold a complete charge.
Unplug the laptop and use the battery until it runs out.
Once dead, plug the laptop in, turn it off and recharge the battery in full.
This may take at least 8 to 12 hours.
Repeat this process at least three times.
Check to make sure that your fan is working.

http://www.daileyint.com/hmdpc/overheat.htm
Check to see if there are any keys stuck/depressed.
If so, use a paperclip and fit it underneath the key and gently pry the end that is stuck.
Make sure the laptop is off before attempting this.
Observe where the boot process ends and starts over.
In most cases, this will give an indication where the problem occurs.
If the laptop reboots early on in the process, for example when it is detecting the hard drive, chances are good it is a hardware issue.
If the reboot occurs further along in the process, like when it is loading operating system files, there may be an issue with operating system software.
Test all power and data leads that attach to your hard drive SATA
the leads from your (motherboard to your hard drive) make sure they have a secure dust free connections and are not faulty
Make sure all leads that are attached to your drives dvd\cd have secure connections and are not faulty.
even something as small as faulty fan lead can cause you problems
computers need all of the data and power to travel through every working device and to have an end for a computer to be able work properly.
Motherboard and a hard drive any leads between them will fail before your motherboard or your hard drive check all power and data leads make sure they are securely seated even the cd/dvd drives need to have current go through make sure these devices are working
Check your computer ram modules for secure dust free seating you might even remove the ram modules to check for dirt on modules and in the module socket and cmos battery make sure it has charge and they are dust free and securely seated some motherboards cmos batteries are soldered in
If your computer runs long enough scroll to bottom toolbar (bottom of screen) right click select task manager
applications you will see whats running
if you see anything you dont need running select end now and you might uninstall that specific
program if you or computer does not require it to run and
some unnecessary programs that could be running your computer over its limits causing memory dumps
also under processes see what is ticking over in the background you might have a virus again if you see something you
dont need to be and users you will see who is using your computer
You might need to add more computer ram
if you're not sure if a module is right for your system use the
Crucial Memory Advisor tool for a list of guaranteed compatible modules. first you will need to select the manufacturer from a drop down list then select your product line
from a drop down list then select the model then click find it will take you directly to compatible ram also you will have an option to scan your system
You should always ask for a guarantee on the compatibility of the ram before making any purchase
Might be getting hot
check you CPU make sure its securely seated and has thermal grease
http://www.hardwaresecrets.com/article/Thermal-Compound-Roundup-February-2012/1490
Capacitors look like small metallic canisters and they are found in many different computer components including computer monitors, computer motherboards, video cards, power supplies and a variety of other consumer products.
A bad capacitor can cause a variety of computer problems, but if you can identify the faulty capacitor you may be able to replace it and save your computer.
Capacitor
Capacitors, sometimes also called condensers, are used to store energy in an electric field.
In the context of computing, capacitors are used to block the direct current being circulated around the motherboard.
A typical capacitor should last up to 15 years, but some computer manufacturers use substandard capacitors resulting in shorter lifetimes.
Computer Problems
When a capacitor has gone bad on a computer you may experience a large range of problems. The computer may have trouble booting up, or it may shut down without notice after running for only a short period of time.
The most common problems associated with faulty capacitors are that they cause unexpected computer crashes and general reliability issues ranging from read/write issues to distorted screen images.
Identifying a Bad Capacitor
To identify a bad capacitor you will need to open your computer case and locate the capacitors on your motherboard.
A bad capacitor may exhibit swelling at the top or the base of the capacitor or it may sit at an awkward angle with the motherboard, so compare the various capacitors in your computer in terms of size and placement.
Additionally, a bad capacitor may have a funny smell or it may have a brownish residue leaking from the top or the base.
Prevention
Manufacturers claim that capacitors may go bad because a computer is not receiving enough power from a power supply, because of an overclocked processor or because a computer is operating in an environment with too much heat or humidity.
However, some capacitors prematurely fail due to faulty work on the part of the manufacturer.
If you have a bad capacitor be sure to do research as to the lifespan of other products made by your manufacturer.
Identifying bad capacitors
http://www.youtube.com/watch?v=ngA4k32jLGc
Capacitor replacement
http://www.youtube.com/watch?v=s0Pn2tEjY04
How to check a capacitor
http://www.youtube.com/watch?v=U4tnHA0phcc
Replacing a leaking capacitor
http://www.youtube.com/watch?v=s0Pn2tEjY04
Could be a problem with the Hard Drive or the Hard drives PCB
http://www.onepcbsolution.com/