Win 7 randomly freezes with HDD light on

Question

I'm struggling with this for some time now. My win 7 x64 just freezes from time to time with HDD light on constantly. I've read almost all threads, tried almost every advise, but just could't solve the issue. 
I have win 7 Enterprise x64 + SP1 installed on PC:
Intel Core2 Quad CPU Q8400 @2.66GHz
Gigabyte P43-ES3G
8GB RAM (4x2GB Kingston DDR2),
2x1TB HDD (WD)
NVIDIA FeForce 9500GT
Next, I'll list what I've already tried (without success) to not waste anybody's time - tried to change hardware, scan HDD for errors, set memory timings, reinstall win, scan for viruses, update all drivers, update BIOS.
(Maybe) important is that the same thing happens in safe mode. However, I've got no problems with other OSs like Linux or Win XP x64.

Answer 1

comibat & ddrouin: Usually when I run into situations like this, the presumption is that its a relatively new issue, meaning, you haven't have this problem from day 1 of computer
ownership.  Right?  So, the first thing is to examine what changed recently?  We should be considering things like, but not limited to, the following:
Application installation or removal
System configuration change
Driver installation or removal
Hardware installation or removal
Windows updates
Etc.
comibat:
When you boot into Safe Mode (with & without networking; that could be key) & let it sit, for a while, does it seem to hang?
When you performed a clean boot & left it for a while, it also hung, correct?
Does it seem to matter whether or not your machine is connected to a network (wired or otherwise)?
If this something repeatable, like within an hour for instance, you may want to load up Resource Monitor & leave it in the foreground until it happens.  When it comes back to normal there should be some results for review.  (It may not update
while its in its hung state, but, when it 'comes back to life' it should show you throughput, usage etc and the process(es) associated with it.  Unfortunately, this may mean leaving the computer on for a while & not touching it.  (Unless
of course its unique to a sequence of events.)
You should consider loading up Performance Monitor as well and creating a counter.  Unfortunately, this is probably something you'll just have to let run until it happens, then make note of the date & time for review once it 'comes back to life'. 
I would do some research on Performance Monitor & how to setup counters.  You could try this counter...
Logman.exe create counter Perf-Counter-Log-1sec -o "c:\perflogs\PerfTest1sec.blg" -f bincirc -v mmddhhmm -max 500 -c "\LogicalDisk(*)\*" "\Memory\*" "\Network Interface(*)\*" "\Paging File(*)\*" "\PhysicalDisk(*)\*" "\Processor(*)\*" "\Process(*)\*" "\Server\*" "\System\*" -si 00:00:01
ddrouin: If you haven't already done so, you may want to consider starting your own thread.  (I haven't checked, just a suggestion incase you have not)  That said: In addition to the
above, is there any commonality between the three systems (the Lenovo, Asus & your friend's computer)?