Pc boots up monitor stays black

[Putrescent]

Hello I have been trying to fix my computer issue for over a week now here is the problem. When I turn on the computer the DVD drive makes the noise likes its booting up but does this for a long period of time then finally SOMETIMES i get a beep. When I get a beep sometimes the mouse and keyboard lights will turn on sometimes nothing. When the mouse and keyboard lights do turn on the HD light starts flickering like its booting to the desktop. BUT the monitor still wont turn on the power light on the monitor just blinks. The monitor is plugged through DVI. I bought a new DVI cord didn't fix it I bought a new video card didn't fix it. I have 4 sticks of 1g RAM I have tried using one in each different slot. I have tried a different piece of RAM to every slot swapping them. I unplugged all components minus HD, CPU, and one stick of RAM and still wont fix issue. I hooked up my monitor to a friends computer with analog and works fine I did same on my computer with analog still nothing. Tonight I took apart everything to barebone and put back together still same issue. Oh I also took out the MOBO battery for 2 minutes and replaced with a new one still nothing. Please help me here are my specs:

AMD Athlon X2 6000
4g RAM
NVIDIA GTX 260
XFI Titanium sound card
Asus M2NE-SLI MOBO
750W PSU

 

[cb600fshornet]

Unplug the PC from the mains, click the power button three of four times, plug the PC back in and try turning it on.

 

[OhSnapWord]

Try a new PSU. If the PSU is failing, it could start sending power surges which would cause the motherboard to go into protection mode and thus not boot.

 

[OS-Wiz]

Could be a bad PCI slot on the mobo, try moving the card to a different slot.

 

[Putrescent]

Could be a bad PCI slot on the mobo, try moving the card to a different slot.

Thank You! Thank You! Thank You! IT WORKED! You are a life saver! I never would of thought of that!

---------- Post added at 12:11 PM ---------- Previous post was at 12:10 PM ----------

Now that I removed the mobo battery and reset the bios will i have to redo the settings?

 

[OS-Wiz]

Thank You! Thank You! Thank You! IT WORKED! You are a life saver! I never would of thought of that!

---------- Post added at 12:11 PM ---------- Previous post was at 12:10 PM ----------

Now that I removed the mobo battery and reset the bios will i have to redo the settings?

You're welcome.
If you're talking about the BIOS settings then yes, any custom changes you've made to the BIOS will have to be reset.