Video output is not detected after reset of initial boot

[dr_mikeymike]

Hello, all!

I am working on a home build computer with a:
Ultra LSP 550W PSU
ASRock M3A770DE mobo
2x2 GB RAM
Sapphire Radeon 6850 HD graphics card
AMD Phenom II 955 processor

Here is my issue:

Having just built my first computer, I power it on and it boots up. However, I accidentally placed the mobo disk in the drive instead of my OS disk. It asks me if I want to create a SATA(?) diskette Y/N, and I find out that my keyboard does not work (this might sound ridiculous, but it's actually an apple keyboard that I placed in the USB drive just to experiment, I suppose that it shouldn't surprise me that it didn't work).

So I pressed the reset button, and my computer resets...

However:

Now, nothing shows up on my monitor. It says that 'video output' is not discovered, as though it was not hooked up right. I have no idea as to what to do right now, as nothing is different. Why, all of the sudden, is there no video output on my monitor?

 

[in_core]

1. recheck your display cable (vga, dvi or hdmi whichever you used) if its connected tightly
2. when you switch on ur pc check (inside the case) if your gfx nd cpu is physically running or not.