Problem with Asus

[reza12100]

Hello All. Thanks for look at my problem

I have
Asus P7P55D LE main
Core i5 760
2*2GB Geil 1066 CL=9-9-9-24
Power Green Gp535B (it is good power with active PFC and real 535watt)
Hard Sata II western Digital green
Ati sapphire 5670

in windows 7 32bit after 1 or 2 hour working، system freezes
first i test anothr ram corsair on Asus P7P55D LE and safety power but system was stable and no freezing happened

I tried install EVEREST Ultimate edition software and RUN SYSTEM STABILITY TEST after few minuets CPU AND Mainboard TEMP go to 64 C° and then go to 73C°
after install this software i do several task:


1-update latest bios from asus site but cpu and main have high temp in EVEREST Ultimate edition test

2-replace vga with ati 5750 but cpu and main have high temp in EVEREST Ultimate edition test(73 C°)

3-test HDD no bad sector or any error showed

3-replace cpu with another core i5 760 cpu but cpu and main have high temp in EVEREST Ultimate edition test(73 C°)

4-test core i5 760 cpu source in another system ،result in EVEREST Ultimate edition test show cpu temp go to 64 C° and mainboard temp go to 40 C° system was stable !

I guess cpu and main in hard working similar matlab going to high temp then system frozen therefore

5-I bought Evercool Buffalo HPFA-10025 FAN and setup for cpu ، result in EVEREST Ultimate edition test show:cpu and main temp was very good but after few minuets system frozen

fan spec:http://www.newegg.com/Product/Product.aspx?Item=N82E16835119091

you think what is my problem?
it is from mainboard or another hardware?

 

[reza12100]

i forget write this:
sametimes that system frozen you can hear continues bugle with no rupture