WARNING: Before you start troubleshooting remember that you are dealing with electricity that can KILL.
http://www.kitchentablecomputers.com/static.php - rules
Test all power and data leads that attach to your hard drive IDE,SATA
the leads from your (motherboard to your hard drive) make sure they have secure dust free connections and are not faulty
if its a 40 pin flat ribbon type it will be the first to fail
make sure all leads that are attached to your drives dvd\cd and floppy have secure connections and are not faulty
even something as small as a faulty electrical fan and its lead can cause you problems
computers need all power and data to continue through every working device and to have an end so any faulty leads will end up with a computer error
Check your RAM.
The RAM is located in the middle of the motherboard.
There are tabs that you can push to release the RAM.
Remove it and put it back in place until the tabs pop out.
Loose RAM can cause your computer not to start properly where you want to see a video signal.
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 alcohol (Methylated Spirits) 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.
Make sure your graphics card is securely seated with no dust built up or in the socket
if you remove your graphics check the socket to make sure its dust free
Restart your computer then reinstall it this should activate found new hardware wizard
Check the vga lead for secure dust free connection or try another vga lead.