Pc won't output signal

i recently bought and build my first pc but there is something wrong:
it won't output a signal to my monitor!
when i start my pc the light turns on, all the fans spin, the optical drive and hdd's starts spinning and the light on the optical drive stars flashing but it doesn't give any speaker error messages

i have a asus f2a55-m lk2 motherboard,

sapphire hd7770 GHz edition gpu

amd athlon II x4 750k cpu

4gb 1600 MHz mushkin ram

2 old hdd which i salvage from a old pc ( both are 7200 rpm)

ewent 600W psu

i have tried to reseed the ram and gpu (nothing happened)

use a old psu (still all the fans spin, lights turns on and optical drive & hdd's start spinning)

reinserted the cmos battery because i couldn't find my cmos jumper ( and also here nothing happened)


i tried to output vga, dvi-i, hdmi through my gpu

and vga through my mobo

is my mobo "dead"? if so please say so because i still got a lot of warranty time left

already thx for al the help i get :D

Can you try going to a friend's house and having them put their gpu and memory into your pc and see if it starts? I don't know how, but I had the same problem as you, except my speakers gave me a beeping error, went to my friends house, put his parts in, took them out and put mine then BAM. It was fixed.

Might just possibly be the GPU, see if you can maybe swap it out for another one to test run it. Also check the GPU fans to see if they are spinning, if not you may have a problem there.... can't say for sure, but seems you have checked everything but that and considering neither input is working, that could be it.

thx guys my friend is coming oversoon with his pc, so he can look what the problem, and btw ilzy the fans were spinning, but thx. but  thankfully i still have warenty so i can send it back and get a new one.