Just my 2 cents
In my situation working on a customers laptop....most deffinately the hard drive. Will remove from machine and verify of course, but the "ear" test tells me something mechanical going on...then you hear the hd spin down (off) right before blue screen.
as an FYI to anybody looking for solutions to this problem, your situation may be related to someone on this post, or may not.
With most windows errors, they are a starting point to trouble shoot from. just look at all the people who had different resolutions to the problem.
in my case, recommend to customer to replace hard drive (2 days out of warranty) and re-install. And be patient with those that are trying to help
pce