Why is my Envy 14y-1200 so tired lately

Hi,
My box specs are Core-i7 720, 8GB Ram.
In the last 3 weeks or so I noticed that the work starts lagging, small freezes.
like when surfing the internet with firefox and the scrolling stuck for a second, or right clicking to open sub menu takes longer or word editing lags etc.
The point in which I knew for sure something is wrong was when installed Cal of duty:Modern warfare 2 - the lags were bad! I couldn't play the game. and this is a game I played before with no lags at all.
the immediate suspect was the ATI 5650 software/hardware.
so I updated drivers - no change
turned off ATI's PowerPlay feature who I saw playing with GPU speed, but no visible change.
the hardware specs are normal when viewing with GPU-Z (imgae attached).

so I decided at that point to benchmark my system and diagnose by the results.
I've done this according to the charts in here
on 3DMark Vantage it scored 3371 which is above envy-14 score in the comparison list.
on PCMark05 it scored 7241 which is also above Envy-14 score in the comparison list.
Windows experience results are the same as they were at the very beginning when I got the laptop.

At this point I started thinking it may be the OS doing troubles.
I'm not a lazy guy - did backups formatted the OS partition and clean installed Windows 7 Ultimate, at this point I made Ghost image to return to if the experiments do not succeed.

I noticed that 11.11 & 11.12 Catalyst driver had trouble detecting my GPU.
so I installed 11.2 driver which went well.
I tried at this point before running Windows update to check performance but to my disappointment the tiredness continues, most noticeably CoD MW2 lags as before.
the temperatures of the system are : 50-60c for cpu on normal use and up to 75c on hi demand, the GPU core temperature is 50-60c .
These temperatures are a bit high I think compared to the first using period, but I think are still in the normal range for my system specs.

I wonder if anyone has experienced something similar and resolved the issue?
I'd appreciate any ideas for further investigations to diagnose the problem.
Thing is if I call HP support, i'll have a hard time explaining and proving I actually have a problem, so I'm not trying it yet.

 

Another point that may be of importance: I'm using Hiren's boot cd. when I'm trying to load Mini XP , the laptop crashes and shuts down when in the desktop loading phase.
I can't remember if it ever worked on this box, can someone make this test for me?

 

I've also been having problems with this just mini freezes like the one's you mentioned. I'm suspecting it has something to do with the hard drive, not sure why but that's my gut feeling right now. I'm still using my stock 7200 rpm 500 gb that came with the computer.

 

Just an update for future reference for whoever has similar problem.
It was a faulty hard disk.
Once replaced, everything went back to normal.