if you just built your computer.  or your computer just stopped booting.  you 
get no display on screen etc. heres how to find what the problem is.

first touch your case the metal part to release any static.   and  unplug your 
computer..   (very important)    take out all cards.   video card,   sound card, 
modems, ethernet..etc  take out the ram.   unhook the harddrive and floppy 
drive, cd rom etc.. pretty much strip your computer back down..

all you should have in your case is.   your power supply  (psu)  your mother-
board, your cpu in the motherboard. the heat sinking fan over cpu.  and the 
little small system speaker plugged into mobo.

now boot up the computer..    you should hear warning beeps coming from 
system speaker. if you do not it is either your power supply, cpu, or mother-
board which is at fault.   if so put in a different power supply if you have one, 
then try  reseating  the cpu  into mobo or take cpu to a local  pc shop to get 
checked. probbly be 15-20 bucks to get checked.. psu tester pretty cheap.

but if it does get error beeps  your motherboard, cpu, and power supply are
most likely fine the error beeps are saying things are missing. now start put-
ting  things back  in to narrow down   your trouble maker.   put the ram,  and 
hard drive in and boot.. alot of the times it is bad ram.  then if that works put 
in the cards one at a time and cd roms. etc and you should find the problem.

i have had the sound card keep pc from booting one time. its usually always 
bad ram that causes this so i always check ram first.