Advent t100 all in one screen blank

I have a advent all in one t100,My problem is a complete blank screen, When I switch on all lights and computer starts up.. you can even hear xp startup but the screen stays blank!! I also think the fan is not coming on!! I have read that this model More akin to a laptop than a desk computer has underpowered psu and that I should replace it with a Delta 220w sadp-220db b psu or a Dell da-2 d220-01(have to alter the wiring but basically similer to the Delta),

My question is:- would the psu be causing the problem 2. does anyone know where I could buy one ( as I seem to be having trouble locating either). 3. or is it something to do purely with the screen ie light ect.. or any thin else??
I really would apreciate all the help I could get..
cpu intel pent 4,chipset intel 865pe

laptops are very very integrated, the PSU is basically a small section on the motherboard, the rest of it is in the battery (for most of the battery control stuff) and in the power brick (for most of the high voltage AC to low voltage DC stuff). So it can't really be replaced, and if you can charge the battery then its probably fine.

What i would do is try clearing the CMOS/reseting the BIOS (check the manual). Then if its under warranty tell them about it, otherwise my guess is the backlight has failed, if this laptop is a few years old i would just start looking into getting a new one, the price to get it fixed is going to most likely be very expensive compared to what the laptop is worth, so you can save yourself some hassle and get a new one.

And i don't know if it helps, but i had a laptop that would do that when the battery was very very dead, removing the battery or charging the battery would make it boot.

Thanks Edman007, The advent t100 is not a laptop, it is a all in one desktop with everything jammed into the stock but I assume with some interior features of a laptop,I think you may be right about a backlight being the problem or part of the problem for the interior fan is not working!! would the screen be turned off! as a safety to the fan not working stop it overheating and doing other damage??