First, please make different threads for different users as the problem might be or not be the same.
Second, we should do this the correct way: Start from nothing and start building. AFAIK, you only need (besides cooling elements), a motherboard, a CPU, a RAM (1 RAM stick at a time), and a PSU. Nothing else to start a computer. Then add ONE part of a time, boot, and see results. Do this and one by one add HDD, the graphics, etc....When you are in Windows, run some benchmark tools for 30-60 mins. This way your components get stressed and if something is wrong with them, they will BSOD.
Third, if after doing second nothing goes wrong (hard to believe but) start a linux LiveCD and see if it isnt some strange driver compatibility issue.