This is a rather long and taxing post so be warned.
I recently purchased a new mb ( Chaintech Summit 7NIF2
I slotted it in but made a few small but potentially fatal mistakes:
1. I mixed the polarity of the lines from the switch-on button on the case. I'm sure I got it right now. White IS for negative right?
2. I may have pressed in my CPU a bit too much when fitting the fan on. But I doubt...anyway...
-When I switched on the PC (with the new motherboard), it started but immediately switched off after five seconds just before the screen showed any text/images. This happened twice as I fiddled with the lines from the on-button LED an the case.
-And now, after getting the polarity right, when I switch on the PC, the power only runs through the mb for a split second. The CPU fan jerks and then "POOF"...nothing.
-The exact same thing is now happening to my old mb, but the light on the optical mouse comes on with the old one and an on-board LED on it shows that there IS some current in the mb. The new one doesn't have such a LED.
-The power line through the adaptor to the screen is OK since the screen is functioning flawlessly.
-I checked (with my laser-accurate naked eye) the new mb surface for any signs of physical damage but nothing shows up.
As deductive reasoning would have it, the problem should be with the case. But I'm an ignoramus when it comes to the cryptic phenomenon of computer hardware so any input from a more apt individual or computer sage would be appreciated.
(in the event that I HAVE indeed "f"ed up the mb, please tell me HOW and whether or not the damage is repairable (and economically viable).)