M3800 cannot see 2nd & 3rd monitors

I purchased an M3800 Precision laptop and 2 P2314H. monitors. I also purchased a Dell D3000 SuperSpeed USB 3.0 Docking Station.

Here's the configuration I am trying to setup:

One monitor connected to the Docking station with a DVI-D cord.  (This one always works)  One monitor connected with a 6ft DisplayPort to HDMI cable (Display in the Monitor, HDMI in the USB Port).  This monitor won't work. 

Here's what I have tried - 

I removed the working monitor completely.  Still couldn't see the new one.

I checked the 2nd monitor to see if it would work by plugging the DVI-D into it, it works.

I removed the Docking station completely, hooked the monitor STRAIGHT into the laptop - it didn't work.

Took the cable back to BestBuy and exchanged it - still doesn't work.

I have rebooted between every series, of course.

The only way I got both monitors to work was to use the VGA adapters - but then I lost my ability to have HD, which is why I paid for an HD monitor.  

Does ANYONE have an idea of what I might be able to do? I am tired of shooting in the dark.

I would be eternally grateful,

Joy