For boards with jumpers the FIRST thing to do is very carefully read the manual to be sure jumpers are set correctly. I'm ignorant about Gigabyte boards, but my impression is that most use jumpers.
For most system-builders, the common problems are motherboard shorted to ground, improperly seated memory stick(s) and improperly seated cpu.
At startup, the only slots that should be populated should be cpu, video card and ram chips. Install other devices after you get system to boot. This also minimizes load on PS at boot.
Check for mobo-to-case grounding by starting up with board outside case or by laying board inside case with a layer of cardboard to isolate the board from any contact with case - no stand-offs attached to board.
If speaker is external to board, make sure speaker connections are OK so you can hear beep codes.
Some boards (Abit) have a thermal sensor under cpu for thermal contact. Some have to bend down thermal sensor a bit to fully seat cpu.
Be very certain that memory sticks are fully seated. Big problem on some boards and with some ram sticks.
Mount cpu and ram sticks with board outside case, for close examination and to forcefully seat ram sticks without damaging board.
Hope this helps!