This Time Headache Mode is real ON !!

Arrrgggghhhhh....!!!!
@$#%!@#%$%...!!!!

Tonight is one of my "aaarrrghhh..." night.

Theres 3 computers won't work.
One is stuck in the lock bar in the wall.
The other 2 is under my reparation.

There's a strange behaviour with this 2 PC.

When I replace the VGA and the PSU, they can work properly
(on my work desk).
But when I put it back to their ussual desk,..
it's starting to have strange behaviour again...
sometimes it act normal...

when get restart/reboot, they wont switch ON properly.
The Other one operate so f*c**n' slowly...
While the other one ..... DEAD ...!!!

this night I cant repair it, too much works on saturday night.
They have to wait until tomorrow.

Hope I cant find what's the source of the problem.
Right now I suspicious that the electricity was not proper or not stabil.
Well never give up, but it get my lazy point....