The first check to make is that the mains cable is properly inserted and providing power and then that the PSU cable to the motherboard is fitted correctly and firmly.
You also need to check the hard drive's cables' firmness and accuracy and equally that the CPU is secure and undamaged.
The Bios or chipset may be malfunctioning and this may require obtaining a new motherboard.
Another reason could be that the mobo may not be receiving a Power Good signal from the PSU (a wire on the mobo connecter used to indicate that it is safe to the system to begin a boot up).
If the Power Good signal is not received it's a similar effect to holding in the reset button and not releasing it. The reason could be that the PSU is not stabilising the power supply or a fault in the Power Good wire).
In that case a new PSU will be required and, if so, then you probably need something with a bit more oomph that 230 watts, especially if you have a good quality graphics card.