Really need help on rebooting computer

[Bill1567]

Hi!
I just built a computer and after a minute or two it shuts off. Th CPU is at about 87 degrees celcius. Here is my build:
Link to a hackintosh site deleted
CPU: Intel Core i3-2105 with Intel HD 3000 Graphics
GPU: None necessary (it's integrated with the CPU)
Motherboard: Gigabyte GA-H67N-USB3-B3
RAM: CORSAIR 8GB (2 x 4GB) 240-Pin DDR3
Case and Power Supply: APEX MI-008 Mini-ITX with 250w PSU.
People are saying I need a 500 watt pw supply. Is that true. I have taken some excess thermal paste off of the cpu/cpu fan. I really need help! Any help is appreciated!!!!!!!!!!!

 

[jmacavali]

Hackintosh computers are not supported here based on the fact they are not allowed by Apple's EULA.

 

[OhSnapWord]

Remove all thermal paste from the CPU and heatsink and apply new paste. It is extremely important that when removing the CPU heatsink, that you remove and reapply thermal paste.