Hey, I think your problem deals with some of your softwares or drivers that you use. Try reinstalling and use load the drivers one by one. It could be Antivirus. I have fixed coms which has this problem
However, my problem is far more troubling. Your's is when you go into windows it WILL freeze right? Mine wont freeze at a fix pattern and it is random, as in there is no way to predict it. It runs windows 7 x64 bit. Uses all the drivers from the HP site. Which I think it's the motherboard's problem because they changed the HDD and Ram, it is still there.
The funny part is HP services claimed that they cant detect the freeze and I had it froze 8 times in 3 hours during my exam.