computer shutting down itself please help

[Pool]

Hi Everyone

Few days ago my computer started to shut down itself after entering
desktop, as if i unplugged it.That happens randomly not all the time.I
checked for errors in the event viewer but their were no errors.I ran a full
scan to check for virus or spyware it came out clean.I opened the case
checked processor and power supply fan they are spinning and no dust inside
since i cleaned it few months ago.Also CPU temperature is 34C so it is not
overheating.I removed RAM sticks and tried another pair of RAM still i had
the same problem.I checked hard drive for errors using error check under
tools it gave no errors.I don't know what else to do.Also my USB mouse
sometimes it freezes for a minute then it works back.Is it motherboard or
power supply.Please help me.Thanks in advance


Computer Specification

Motherboard : Gigabyte Intel 865PE
Hard Drive: 80G Maxtor
RAM: 2X1G DDR Kingston
Video Card: Radeon 7000
Operating System: Windows Home SP2
Power Supply: 450 W Gamma

 

[Peter Foldes]

First thing to look at and usually is the culprit is the PSU which is overheating.
Put your hands to the PSU fan exhaust and see if it is clearing the hot air easy. If
very slow on the exhaust then it is your PSU

 

[Pool]

Hi Peter

Thanks for replying.I checked PSU fan exhaust at the back of the computer
little air is coming out , i checked CPU temperature it is 34C.Also a while
ago i experienced a strange thing.USB mouse froze cannot move it but i can
still scroll and click on buttons.Could it be due to insufficent power
arriving from PSU.Thanks again.