Keeps shutting down :(

Right here we go:-
my computer that i have just built keeps turning off, basicaly unstable. i beleive this is due to something to do with the memory set-up in my bios?

The motherboard i have is a ASUS m4a79xtd EVO with a AMD Phenom II x4 Black Edition 3.4 processor socket am3.
i have installed kingston hyperx 2x2gb ddr3 modules 1600mhz, part number khx1600c9d3/2gb

can anyone help me or give any advise?
just anything! haha

please bare in mind i am a bit of a noob to all this

It is none of them, the pc turnes on and i have installed windows 7 on it fine. it runs but randomly turns off it was first doing it when scanning for new channels on windows media player through my tv card but now it is always doing it, im not a time waister, oveosly i didnt make my problem clear to you, sorry.
it does boot up fine as i am using it to write this and all drivers are installed.

cheers, sorry if i have caused any trouble. i dont mean to waist time.
i have set the bios to defaults. an taken one ddr3 out leaving the remaining one in.
there are no traped wires and no cable ties around any wires or anything of that sort.
nothing is lose inside the case.
after setting it to default i am tryin it out with one stick like you say, as weird as it sounds it never failed to do the fault when scanning for new channels on windows media so i am doing that to see if when it comes to 90% complete it still closes like before.
it doesnt just do it when scanning for channels by the way.

so we've tried both sticks and different slots still getting the error

means most likely the mem is good so; on to the power supply, and without a tester your going to have to swap it, hopefully you have another computer to borrow it from or a really good friend that will loan you one for a day

sorry my mistake,
so we are down to only one stick of ram, and everything works fine

you can try to reinsert the other stick; if one was lose that could have been the whole problem

FYI
both stick should be in the same color slot ! ! !

if life isn't that simple

run memtest on each stick of ram to see if one is faulty, it they both pass

run memtest on them in each set of slots,

if the sticks pass and the board fails we found the problem, and you replace the problem
alternately we can try to compensate in the bios

if each stick can pass then they are good,
but if you can't get the pair to run then the fault will be with the MB

if your at the fail safe settings in bios it's the mb

of course some times you can compensate by adjusting the settings

glad it's working for you

if it's not defaulting to the right setting I would change them, just remember if you do it manually you have to make sure all settings are set correctly speed, vol, cas