PC Reboots when large Applications are opened

[abhishekchhabra90]

hi
this my question
my pc is making me crazy from one month i've been
trying every single attempt to correct it
now here's my problem:
i turn the pc on windows load perfectly bur
pc is rebooting whenever i play any large applications

CONFIG:
Intel core i5 760 base 2.80 ghz,
gigabyte h55m-s2,
psu-cooler master 600w,
Ati redeon HD 5770 1gb,
ram 4gb 1333mhz kingston
1Tb segate

obviously i thought of some problems:
May be:
1.smps is causing the power problem
or
2.motherboard is causing h/w problem
or
3.processor is unable to divide the threads
or
4.graphic card is making the pc reboot when bigger application runs
so i took the rig to service center for diagnosis and they replaced the mobo,smps,ram even the processor but the same thing hapend "REBOOT"
but a stange thin happened i own psu " cooler master 600w " worth Rs3500
and when the service man replaced the power with his psu "zen 460w" worth Rs450
pc dint reboot then i again replaced my psu..... and with my bad luck again a "REBOOT" occurred now just my graphic card left for replacement i dnt think theres any problem with it .. this is first time when i cant figure out what the problem is PLZ help if u can thnx ..

 

[a_tractor]

maby its your psu

 

[alvine]

its either the psu giving up on you slowly or its the memory

 

[abhishekchhabra90]

its either the psu giving up on you slowly or its the memory

yaa but memory is replaced too