Help me please

[Tabiashi Yoshita]

A while ago my uncle gave me some 2012 or something desktop and it had a broken CPU, No RAM, No GPU (it has intgrated graphics but)... So i decided to fix it a couple weeks ago and suprisingly it turned on! but after 15 minutes it shut off. I pressed the power button again and it turned on and off. I rebuilt everything and it did that same thing, I figured it was the power supply because it was old and dusty. I have a spare 500W ARESGAME Power Supply so i tested it and it was fine and then i put it in and it did the same exact thing. I even reset the CMOS Battery,  I appreciate any type of help!

[Radium_Angel]

Need full system specs, plus pics of the build (the guts, not the case)

[Tabiashi Yoshita]

6 minutes ago, Radium_Angel said:

Need full system specs, plus pics of the build (the guts, not the case)

I'm not home right now but i can provide you with the specs.

Motherboard: ASUS M4A88TD-V 

CPU: AMD Phenom II X4 965

GPU: NVIDIA Geforce GT730 

RAM: Patriot 4GB DDR3 Single Stick

HDD: MAXTOR 120GB 7200 RPM

[Radium_Angel]

Could be overheating, you got fresh thermal paste between the CPU and the CPU Cooler?

[Tabiashi Yoshita]

1 minute ago, Radium_Angel said:

Could be overheating, you got fresh thermal paste between the CPU and the CPU Cooler?

Yes, It had pre-applied thermal paste but i still put some MX-4 on it 

[Radium_Angel]

2 minutes ago, Tabiashi Yoshita said:

Yes, It had pre-applied thermal paste but i still put some MX-4 on it 

Monitor temps at idle, see what happens when it approaches the 15min limit

https://www.alcpu.com/CoreTemp/

If temps are good, then you have bad hardware elsewhere. mobo perhaps