Precision T5500, diag lights looping

Hello,

I have a Dell Precision T5500.  It was a working machine, I did add another hard drive and I moved it from where it once was to another spot.

The machine saw and worked with the new hard drive and that was before moving it.

So now it behaves as follows:

Turn the power on and the on button is green, diagnositic lights flash, 3 4 for awhile then it goes to 2 for a brief moment then it goes 1 2 3 for a bit but then a slight click a flash at the lights and it repeats from 3 4, followed by 1 2 3.  Its locked in that loop. 

Screen shows nothing, its black.

I have checked the connections on the graphics card, and the ram.

1 2 3 code indicates possible hard drive connection so I checkd that too, but still the same issue.

Anyone have similar situations and know a fix for this?

Thanks.