guys, just helping out a friend's issue with her PC... basin naa moy inputs

kay hasta ko na weirdohan sa problema, ehehe...
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IT friends need your help!Im getting paranoid on this 5month-old desktop. Here's the problem
System won't turn back on after shutdown, I have to wait 5-10mins till it goes back to On-state. For instance, when I click on shutdown, system turns off then when I press the power button to turn it back on, the LED fan ran/lit for a second then it shuts off. I have to unplug the power cord, usb devices, LCD monitor, then wait for 10-15mins until it gets back up.
But if I put on the system to sleep mode, it's like in standby mode (fan is off, power button LED light is blinking) then Im gonna press on the power button, system turns back on the current state. No issues with sleep mode and restart!
I went to PC Options to have them check at first they said it was grounded, it was working for a while then it started to act like crazy again. So I went back to Pc Options, they tested the memory, used a different power supply, reseated video card,etc. but no LUCK. So they replaced the MOBO, and tested everything. Tried shutting down many times, it was OK!!! So I went home and plugged all the chords.
Turn on the system,then tried shutting it down. Turn it back on, unfortunately seconds lang deads agad ung fans! i tried pressing the power button, no GOOD!!hayz headache!
I'ved checked BIOS and load default settings!, system restarts then it shuts off! same thing I have to wait 10mins.
I checked diff forums can't find any related issues.
btw, Here's the specs
OS: Win7 ultimate 32bit
CPU: Intel core i5-2500 3.30GHz 6MB Cache 95 Watts
MOBO: MSI H67MA-E45 Military class II
Memory: Kingston 4GB
Videocard: NVVIDIA Geforce GTS 450 1GB DDR3
Power supply: Thermaltake Litepower 600W input voltage 100V-240V
HDD: Seagate 500 GB
Casing: Thermaltake V3 black
Please note: No overclocking done, no overheating
BIOS is updated
Help me guys! Thanks!
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