PC starts up but nothing on screen

[Trancidonia]

Hello everyone
I finally got my rig back from my brother like two hours ago.
PC was fine since i was using it before my brother give it back to me.
He told me that both my harddrives are basically dead.

so i bought a New Harddrive.

I just need some clarification that
i know that both my harddrives are dead but thing is that i am able to start it up to the point that it hangs with the harddrive started clicking or already clicking and that was before i lend my rig to my brother.
but at least the Monitor screen showed something like the motherboard brandname and everything or Bios.

But right now, there's nothing on the screen, there's no beep, everything is turned on, the harddrives however is not clicking at all when i tried on 'em. the GPU is working too, the PSU is fine since im still able to use the PC this earlier evening.
Should these thing happens when there is no harddrive(nothing on screen)?
Should i plug in my fresh empty harddrive and cross my finger or even put my Window7 CD into the diskdrive?

Right now im just afraid to do anything stupid and screw up my Lifeline which is my PC.
I'd tried to search similar problems that probably had happen to anyone in this forum but i am not sure.

[solved]
got a feedback from my brother
apparently the 3d card is not propally seated

 

[B00kWyrm]

If transporting the rig was enough to "unseat" the graphics card,
there may be other issues as well.

I would load CrystalDiskInfo, for a quick check of drive health.
Download CrystalDiskInfo from CNET, here.

If it finds any problems, you will see the warning.
Migrate your data and prepare to replace the faulty drive.

Also, make sure the fans and any heat pipes (or plastic ducts) have not become dislodged from their proper place.

 

[Ekildog]

When i move my computer i usually get the 20 pin connector loose