Help with my New Build

[emoney123]

I built a computer for my brother and I installed Windows 7 on it. Everything is working but after about 10 minutes of being on it, it freezes up and i cant move the mouse or type. I cant even get into task manager. I have to do a hard restart. This keeps happening. I switched out the graphic card with the one in my computer so its not that, and i ran a disk check and nothing came up. I am thinking its the memory. I am not home right now but when i do i plan on switching the memory out with mine (We both have the same parts basically) and see if it stops. Any other ideas on why it could be doing this?

 

[DANWIN]

did you install all of the necessary drivers first?
it's either that or the your parts.
post build please.