wierd pc boot problem

[poisonclay]

Badly need your your help guys to identify the problem of my pc.

system specs:
AM3 - mobo
athlon2 - proc
1GB RAM DDR3
HD5760 graphics card

it was perfectly working until one day when i try to turn on my pc, it wont turn on at all.
i tried to personally diagnose it by replacing the power supply, removing the graphics card and connect vga directly to mobo. i even ask one of my friends to connect their HD to indentify if theres something wrong with my own HD, and when i tried to turn it on again, the blue light on front panel went on but no red light but all the fan is spinning, i tried to unplug all the other peripherals but its doing the same thing. a consulted it to one of my I.T. friends to check whats the real issue but he also had a hard time. i went to PC express and they had to replace the power supply and when they turn my PC on, it boots up and run perfectly OK. so i went home with my PC and when i try to connect the VGA and power cord,. it does the same thing again. but this time whenever i turn on my PC, its giving me an inconsistent respond, sometime it will turn on for a 1 to 2 secs and die, sometimes, it will have the blue light but no red light with all the fan inside running, or it will have the blue light and red light (not blinking red) with all the fan inside running. so i decided to go back to PC express and when they try to turn it on at first attempt, IT WORKED! crazy indeed and they just ask me to get an A.V.R instead. I left it there for 7 hrs so that they can check all my spare parts but all of them are in good shape. so i went home my PC and surprisingly, its doing the same crazy thing.
So i decided to consult my PC issue to PC gilmore and it worked on their fist attempt to turn it on, there was just a display error where changing monitor resolution resolved it. I have a 21" monitor and i also connect my PC sometimes directly on my 42" TV. they even checked all my parts and got the same answer from PC express technician. I was advised to replace my VGA cable, but it did not help it at all.
Is there anyone here experienced this wierd situation where both PC express and PC gilmore technician had a hard time to figure out the problem. my PC turn on without any problem on their shop but wont work at my home even if i tried to connect it to diff monitor, power supply and all parts that has been checked and verified by both PC shops.

I will really appreciate all your responses.
Thank you

 

[Phillip Corcoran]

Has to be something outside your system altogether. Something wrong with your domestic mains supply I'm thinking, or maybe just in one particular wall socket. Try it in different rooms if you can, just as a test.