Deathrow

Hey, Im sure you've heard of that term used in the IT world well now its happening to me

Ill be playing a game like call of duty 2, guild wars or dawn of war for example then after say half an hour to an hour (happens randomly) the game will freeze, sometimes makes a weird noise does the pc and then a blue screen appears but there is no error message. I then have to restart manually and then it will be on for a while till it happens again.

Points:
It happens on most games if not all
I bought a new 300 gig hard drive recently (could be related)
My PC has played these games fine before and is a high tech gaming pc
Ive tried restarting the pc using f8 and 'last known good configuration' doesnt work.

My spec:

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O/S:Windows Vista Home Premium 64Bit SP1
CPU:Intel C2Q Q6600 (G0) 3.65GHz w/Thermalright Ultra-120
MB:XFX 780i P04 Bios
RAM:4GB OCZ DDR2 Reaper EB Edition 810MHz|4 3 3 8 2T
HD:150GB WD Raptor
GPU:XFX 9800GX2 1024MB|700MHz GPU|2.2GHz Mem|1750MHz Shader
Monitor:Samsung 22inch Widescreen
Sound:SB X-Fi Xtreme Gamer
Input:Steelseries 5hV2 Headset|HABU Gaming mouse|Saitek Eclipse2 Keyboard|Tagan BZ 1300W PSU | 3DMark06:18,144