My brother just did a rebuild on his computer, but the machine fails to boot windows properly. It goes through the Win 7 load screen, then quickly blue screens and restarts when it's supposed to go to the login screen. We initially thought this was a RAM issue, especially since BIOS showed only 4 GB of the 8 installed and at a lower clock speed than the DIMMS were labeled (1066 instead of 1600). He tried each individually, and while neither showed the correct clock speed it still would not boot. Trying an extra DDR3 DIMM from a different machine produced the same result. He tried all different RAM slots on the motherboard to no avail. He lists the parts as follows:
Asus M5A99x evo motherboard, AMD FX6100, corsair vengeance DDR3 1600 (2 x 4 GB), GTX 560
I can tell you that you are at risk for all kinds of problems off the top of my head.
If he is trying to move the old hard drive to a new motherboard, Windows is likely to need to be reinstalled.
Corsair RAM has about the highest fail rates out of any of the major manufacturers. Crucial and Kingston tied for the lowest, and both 5x+ less problems than Corsair RAM. Try downloading MemTest86+ and running that and see if you get a bunch of red marks (bad). It is best to run this while you are sleeping as getting 10 complete passes is ideal.
Also, FX processors often don't work right out of the box even if the motherboard says it works with FX processors. Often you have to do a BIOS update on the motherboard to get it to recognize the FX processor right, which means you have to have another AMD processor just laying around that you can insert to do the BIOS update with.
Those are the first 3 glaring things that jump out at me. Your problem is reasonably likely to be one of those.
It's not likely it's the RAM. He pulled out the Corsair and ran it with DIMMs of Crucial from another machine that works. I considered the Windows reinstall but after reading about RAM problems causing a similar problem I thought there might be something I overlooked.