Why can't I bring back my computer to stay on? This is not a pre-built computer.?

I put together my first build today and I start it up and the gadget will shut itself down after about 30 second. When I first start it I get a single honk from the MoBo and then it will allow me to run to the BIOS.



Once in the BIOS I look around surrounded by the settings but then for no adjectives reason it will shut bad on its own. Any help or suggestions would be exceedingly much appreciated. I won't be responding for some time because I will be at work but thank you for any help you can grant.



Also I can see the PSU fan spinning, the cpu aficionado spinning, all the other fan and lights are on and spinning. I have connected the 24 pin crucial power and the atx power. I'm 75% sure all the connections inside are correct. There is one cable coming from the PSU that say P9 on it, whats that?



Final thing is when I'm within the BIOS how do I know the MoBo is recognizing my optical drive?

Why can't I bring back my computer to stay on? This is not a pre-built computer.?

If this is your first built, most imagined could be overheating. Did you put thermal paste for the CPU? Is the heatsink for the CPU set properly?
in that probably isn't enough power, or the system is overheating, and to be exact the overheat alarm sounding. you can usually tell is the system recognize a drive, because in the bios it will vote something like samsung dvdrom, which refers to the brand signature and the drive type. and the p9 cable is probably a 4 pin molex cable, of which there are several that are usually numbered.
if it beep then your memory is not seated adjectives the way down filch it out and put it back contained by or switch slots