Moniter doesnt show anything

Check display without cabinet maybe motherboard getting short with cabinet and try new Power supply check all the power supply connectors connected or not .

There should be some sort of beeps then. No beeps is an indication the CPU or RAM is not seated properly. You need to refer to board manual if there are beeps.
There is also the matter of... Never mind I just noticed the CPU is an 8 core CPU, but the board supports quad core.
Board specs
http://www.gigabyte.com/products/product-page.aspx?pid=3833#sp

CPU Specs
http://www.newegg.com/Product/Product.aspx?Item=N82E16819103960

Double check my findings and go from there. Good Luck

So it seems you had a bad MOBO ,PSU or RAM.

Hi

Try to boot with 1 stick of ram then swap it with the other and try again. Next unplug the case front connections from the mobo header (pins). Draw a sketch where they all go so you don't forget. I'm talking about the power switch, reset SW, HDD LED etc. Also remove anything connected to the back panel printers etc. Also remove the mouse and keyboard. Carefully, momentarily short the pins that were connected to the power switch and note results.

If it still doesn't boot, remove all parts from the mobo except 1 Stick of RAM, graphics card, PSU, and of course CPU. Leave the mouse and keyboard unplugged. Try to boot by shorting the mobo pins again. If it doesn't boot it is most likely either the PSU or the mobo. It could also be the CPU or RAM but it is less likely.

Please get back to us if you have further query else please accept the suggestion.
Thank you for contacting fixya.com

just dump everything and buy a branded new PC....
u will be increasing ur BP....it;s not worth this much effort....
the kind of work u have done...it seems ur an expert so u urself work it out what's wrong...and where did u make a mistake...

i guess ur CPU and MB are not getting along....some issue with ur integration.....of all parts....

You've tested the PSU for volts, although you didn't mention the +12v, the critical thing with all PSU's though is Amps, if there is insufficient amps the CPU will not initiate properly, modern CPU's mobo north and south bridge chips Graphics chips etc are power hungry, volts are one thing amps are everything. Try and borrow a friends PSU to test, then buy a good one if it works with at least 14 amps on the +12v rail, the higher the better.

if the moniter light is keep lighting than there will be problem with your video card check the cable connections of your moniter . if ot not work than change your video card.thanks and take care 

While booting BOIS goes for POST check for detecting the all the hardware .

Disconnect all the connection to DVD, HDD, FDD from MOBO.
Rmove all RAM and start the ssytem from testing RAM Serviceability. If you listened a long intermittent beep place a single pices of RAM in MOBO ( repeat test with other RAM also).

Other wise your video card is unserviceable, if you have any addon plugins like NVIDA graphics card you can check

remove your video card and plug it again.. if it doesnt work..
try plugging ur video card to *********** board built in video card and then ur on-board video card to you monitor..

this is what the nvidia guys mentioned on their video while announcing the release of the 9 series

The burning smell (if it was a fishy type smell) may have come from the mobo psu 21 pin connector where you plug in the psu. The connection may not work properly because of melted plastic deposits which may be why you are unable to turn it off at the switch. Just check the old psu connector for signs of rusting pins and mis-shaped connector. If you have a fairly recent mobo and processor ensure that the power supply doesnt need the power supply from the psu, unlike some processors where the power is taken from the ZIF mobo socket.