Could also be the memory. Did you get the memory and motherboard from the same place or different?
For that matter, I have seen cheap power supplies cause errors like that, especially if they were under sized.
It's not worth it. If I want it custom built, I'll either work with a local shop or find a place on ebay that looks like they do a lot and will let you tweak the config. Unless you are doing several at once, it just costs too much to build your own, especially when you consider your time...








