Motherboard Shows No Response At All

Do you know the PSU is good? Can you test it with another system?

No unfortunately i dont have anything else to test it on. neither do i have another psu to test the mobo.

I just did some research and found out that the 400w model has only 3A but the next model in the series (500w) has nearly 3 times more - 8A which in comparison makes the 400w look very weak. Could this be the reason the motherboard is not reacting to the PSU current in any way?

The numbers do not make any sense unless you are talking about AC input power which really does not matter too much.

The key figures are 12 volt capacity. A bit of googling indicates that the 400 watt PSU has two 12 volt rails, each with a maximum of 18 amps. However, total capacity is 300 watts or 25 amps.

You haven't told us the rest of your system spec, particularly the video card.

Novatech's are not particularly high quality units. Yours could either be defective or overloaded by a video card that needs more power than the PSU can provide.

Ok the specs are
i5 2500k
Asus P67 Pro
4GB Corsair Vengeance
Nvidia 9800GTX+ (temporary)

Also I found out that the Novatech PSU are OCZ MODXs in disguise except for the 400w model which OCZ doesn't sell so probably the 400w model is very poor quality but even if so why does it show no response at all, if the PSU was faulty or just too weak it should still atleast attempt to boot.