Hi,
No you don't really need to do that just disable the basic things. At this stage all we are trying to do is find out exactly where the problem lies. I think it could be with the HDD, as I mentioned before but, it really is a process of elimination.
The reason I feel it is more likely to be a hard drive issue is the fact that everything has passed all the tests you have thrown at them. Also the fact that you're not getting BSOD's rather that your system is freezing, also points towards this. If it were RAM or CPU then I would expect different symptoms.
The only times I have come across a system freezing, in the manner you describe, it has been either a hard drive problem, power issue or a bad install of the OS. I believe your PSU is OK and also you have had the same problem despite installing different versions of Windows. The only thing that you haven't changed is the HDD. If the HDD is locking up or failing then it would exhibit this "freezing" of windows, because the OS is waiting for the disk and is unable to progress because that access isn't occurring.
If, after you have re-flashed BIOS you are still getting the problem then the next thing would be to look and see if there is a firmware update for your Samsung drive or try a different make.