Solved PC using Samsung 1080p TV as screen, image doesn't look HD

I'm not sure if this is the right category, if not any suggestions welcome.

I am having issues with using my TV as my computer screen. I received an HD TV for Christmas, but I have never been able to get that high definition look its supposed to have. When I run even 1080p bluray quality videos, the quality is just not there. I can sort of make it look better through the TV's menu, but the quality is severely compromised as I have to bring Sharpness WAY down to compensate.
To be clear, the image looks bad everywhere on the pc, not just when watching a video.

TV is I BELIEVE (at work, will have to confirm when I get home) :
Samsung® UN40H5003 40-in. 1080p LED HDTV

PC is:
Dell Inspiron 660
GeForce GTX 760 Graphics Card

Connection is through HDMI ports

I have searched everywhere for this answer, any help would be appreciated.
Also, I have already tried changing the device name to PC in my TV menu, that
is not the solution.

 

TV hardware is fine. Looks fine when connected directly to BluRay (borrowed one for test).
The resolution on PC is 1920 X 1080 (only 1080 option) and same goes for the Nvidia menu.
The TV is brand new, not 2 months old.

 

Sorry, I wasn't very clear. When hooked up to a BluRay PLAYER (seperate device, not going through PC) ,my TV appears to be in full HD.
When running a BluRay video FILE from my PC (no disk), it doesn't look HD. Nor does anything else on PC.
No help in the manual unfortunately.
PC Input it HDMI

 

The other problem you may have is one of expectation. How close to the screen are you when using it connected to a PC? With a 40" TV it is designed for viewing from at least 6 feet away. If using it as a PC screen you are probably much closer than that and may be seeing the individual pixels. Also what resolution is your PC outputting. Ensure that it is set to 1920 x 1080.