my computer always shutdown. it takes only a minute after i turn it on then it shuts down, then when i turn it on again it wont response then ill wait for a a seconds to turn on again if it will WORK but unfortunately the result it comes for the same result.

i troubleshoot it, i disconnect the hard drive and optical drive so i leave the motherboard, processor and memory inside the system and then turn the pc on but it still dont work. i think the problem is either the processor, or memory or the motherboard. what do you think the possible problem with this?

thanks in advance guys
http://en.wikipedia.org/wiki/Thermal_grease

http://www.techpowerup.com/printarticle.php?id=134

just READ it,try,then tell us.Check or swap the power supply, just to eliminate it as the source of the problem.

Take a look at your capacitors as well, are any bulging or leaking or CRUSTED? These bad  caps will take out the motherboard .Could be power supply? Could be heat related. Make sure all fans are running>check heat sink mounting to the cpu>thermal paste like in other post could be the pblm?>CLEAN all lint & dust from inside the casei try all your advise and i found out what the problem is, the heat sink was not attached PROPERLY that's why it always shutting down. OMG, i thought i will buy a new one. thanks for the help guysYou welcome, that's what we do.