WARNING: Before you start troubleshooting remember that you are dealing with electricity that can KILL. http://www.kitchentablecomputers.com/static.php - rules Only work inside the computer case when the power has been switched off and disconnected. Never open the power source. Some of the below steps recommend removing physical parts within the computer. While in the computer it is highly recommend that you be aware of ESD and its potential hazards Remove the memory modules from their slots. Take the opportunity to clean the slots on the motherboards and the memory module connectors. Use compressed air to blow dust away and clean contacts with a soft cloth. Do not use a metallic vacuum cleaner if it touches any component it may create a short and cause damage to the motherboard or other components. Do not use solvent that may attract dust and never poke things like cotton buds in to slots. lightly rub an alcohol on a cloth not to hard let the alcohol do the work on the copper gold or silver tabs and r Allow the pins to dry. They will air dry in a matter of minutes If reseating the memory did not resolve the issue try swapping the location of the memory. If you have only one stick of memory in the computer try moving it to another slot and then boot the computer. Check the memory module and memory slot contacts. They are either copper tin or gold. The colour will tell you which they are. Mixing tin and gold can result in corrosion that prevents proper contact. Look for any sign of physical damage to the memory module, memory slots or the motherboard. Reseat the memory modules. You should hear an audible click when they are in place. Do not use too much force to reseat the memory module in to the slot this can cause damage to the module, slot or motherboard. Could even be a virus or malware Download and install at least one of these all free depending on your operating system http://spybot-search-destroy.soft32.com/ Freeware detect and remove a multitude of adware files and modules. http://www.majorgeeks.com/Microsoft_Security_Essentials_for_Windows_d6242.html microsoft security essentials your operating system must be registered http://windows.microsoft.com/en-US/windows/products/security-essentials/product-information malware protection http://100-downloads.com/download.php?p=615 windows xp microsoft security essentials http://100-downloads.com/download.php?p=614 windows 7 microsoft security essentials Thermal compound is a sticky paste that is placed directly onto the CPU. http://www.hardwaresecrets.com/article/Thermal-Compound-Roundup-February-2012/1490 Allowing for a more direct heat transfer between the CPU and HEAT SINK and preventing air gaps from forming between the CPU and heat sink.
The hardware that you are trying to access is damaged or failing.

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 b> 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. b> Identifying a Bad Capacitor b> 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 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. b> Prevention b> 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

The device drivers for the hardware are faulty or incompatible. Could be a problem with the Hard Drive or the Hard drives PCB http://www.onepcbsolution.com/ There is a connection problem such as a bad cable
Test all power and data leads that attach to your hard drive SATA
the leads from your MOTHERBOARD TO THE HARD DRIVE make sure they have a secure dust free connections and are not faulty. Although it would be very rare for the sata lead to be faulty. Make sure all leads that are attached to your drives dvd\cd have secure connections and are not faulty Computers need power and data to travel through every working device and continue its cycle and have an end so any faulty leads will end up with a computer error