Windows Vista random shut down

HI,
I purchased one sony vaio laptop model vgn cr 24g two years back and it was preloaded with windows vista home premium. Some six months before it started shutting down in between and when I restarts it is not prompting for any safe mode or normal mode etc and starts up normally. Initially the frequency was less but it increased and I went to the sony service center. They replaced the motherboard bcz they found that it was the problem of chipset. But after servicing also the system shows the same problem - shutting down intermittently- In the event viewer also it is not showing anything. Please any body can advice me to find out the correct problem.

Regards
Sree

 

Hi,
I shifted this topic to Hardware discussion forums.

 

I will close this thread. Please don't start threads in more than one forum at a time about the same topic, it is double-posting.
[Edit: You can request that one of the forum moderators move the thread to another forum.]

For those interested this is the thread in the Hardware forum
http://www.windowsbbs.com/hardware/91922-random-shutdown.html