AMD computer often failing to restart from Windows

[Tomcat76]

This is a peculiar problem I've been having with one PC.  It was originally running Windows Vista 64-bit, but later formatted and loaded with Windows 7 64-bit.  I can't remember if the problem already existed when Windows Vista was still installed, but I presume it was because I now feel this to be a hardware problem.  When hitting Start > Restart, I expect Windows to shutdown, the computer to restart, the POST to load, etc.  However, something seems to be going wrong after Windows closes: the screen goes black as expected, but the POST never appears.  All fans and hard drives are spinning and all lights are burning.  The only way to get the computer running again when that happens is to either press the reset button or to shut the PC down and power it on again.
 
The motherboard in question is an Asus M4A87TD EVO.
 
I have tried to fix this on various occasions over the past year or so, without success.  Some people suggested to disable the power saving settings on the Firewire port, but I had already done that before (out of habit).  So I did the reverse, and re-enabled the power saving settings but that didn't help.  Next, I disabled the Firewire port but that didn't change anything either.  Recently, I also read somewhere that it could be a keyboard incompatibility; some people have fixed this by swapping their keyboard.  This didn't seem to help me either.
 
On the VERY odd occasion, over the past week or so, I have noticed the computer to shutdown instead of exhibiting the problem above, as if I clicked Start > Shutdown instead of Start > Restart.  Don't know if that's a clue.
 
Is there anything else to try?  Change the power supply?  Flip the connector of the reset switch cable in case it wasn't connected the right way?  Change the power state setting in the BIOS (currently set to "S1 only")?  Reload the latest BIOS?

[i430VX]

Try changing that PSU out for a different one.

Reloading the latest BIOS is worth a shot, too.

[puntoMX]

Indeed, try S3 and not S1, install the, non MicroSoft, AMD chipset driver from 7/29/2015. It doesn't sound like a hardware failure to me.

-Ronald

[Tomcat76]

Thanks for the input.  I'm going to be placing a new PSU in my own PC and offload my current PSU to the AMD computer.  If that doesn't help, I'll try changing the power state to S3.  The AMD chipset driver is already installed, though I need to check which version.  I thought it was the latest.

[Tomcat76]

The PSU and video card were replaced: no problems thus far.
It looks like it was a PSU problem.