Computer powers down during restarts

[ben29]

Hello
i'm new to these forums, but i really need some help with my computer!
I recently put a computer together with all the spares i had lying around in my room, it all starts up fine and works correctly but when ever i need to restart it, everything goes smothly until its about to start up again when it suddenly powers off. and then if i try and swich it back on it briefly powers up for about 1 second then switched off again and then if i unplug it and plug it back in at the main, it switchs on and sounds like everything is working but then there is no signal to the screen, i switch it off and leave it for about 15mins then come back and switch it on and everything works again. until i need to restart it again when the same thing happens! I have tryed changing the power supply but the same thing still happens. please if anyone has any ideas it would be very useful.
Thanks
Ben

[GX1_Man]

What are the particulars on the components? Did it ever work correctly when patched together?

[ben29]

spec as follows
Asus P4S800 mobo
Intel celeron D 2.94ghz
1Gb ram
200Gb hard drive
nvidia pny 6600
aquagate mini liquid cooler
had a 400w psu then i changed it to a 300w psu to see if that was the problem but the same thing happened

ever since i built it it has down the powering down during restarts
Thanks
Ben

[GX1_Man]

Is the MB shorting out on the case? Are you positive it is assembled correctly? Have you done this before?

[ben29]

im pretty sure its all assembeled correctly i have built quite a few computers yes like the one im using now which works great, where would it be shorting out if it was? and why would  it only do it when you restart it?
Thanks
Ben

[GX1_Man]

Some screw touching tthe case, contact at a standoff, etc. It would be unusual to ONLY happen then, but you never know. What  is the heritage on those power supplies?

[ben29]

What does heritage mean, if you mean where did they come from the our both out of other computers but where working fine in thier!
Ben

[GX1_Man]

Manufacturer?

[ben29]

The 400w that was in there before was made by Win Power i think not sure about the 300w one that is in there at the moment!

[Fed]

Did you do a clean install of the operating system or just stick in a HD with an existing OS?

[ben29]

i put the hdd and dvd and cd drives onto an existing motherboard and prossesor without reinstalling the os yes! why does that matteR?

[GX1_Man]

Yes, it absolutely does matter. Would you/could you do a reinstall if it solved the problem?

[patio]

The 400w that was in there before was made by Win Power i think not sure about the 300w one that is in there at the moment!

Dropping your wattage by 100 amps is probably starving that machine...but i also agree with GX1 Man. If it is a newer OS you can't just swap an existing HDD onto another system and have it run properly.

patio.  8-)

[Fed]

Watt?

[Arc]

[highlight]Dropping your wattage by 100 amps is probably starving that machine[/highlight]

Maybe LOL