Can't get gtx 660 to work

[Moose2_45]

I've got a hp pavilion 550-136na desktop and I'm trying to run a dedicated graphics card as well.
Now I bought this second hand and have not got any of the discs that come with it when you buy it.

When I install it into my pic and reboot nothing is shown except for the standard integrated graphics card.
How do I get this to show as my new gpu?
And I can't download any of the driver online as it says that there isn't any nvidia software compatible and cancels the installation of the drivers

I even went out and bought a brand new power supply which should be more than enough to handle the graphics card.

Any help would be appreciated and I'm not too technical when it come to pc's.

Here's the link to the pc specs
http://support.hp.com/us-en/document/c04791391

This is the link the to graphics card specs http://www.geforce.co.uk/hardware/desktop-gpus/geforce-gtx-660/specifications

And here is the link to the new power supply that I have http://www.corsair.com/en-gb/cx-series-cx500m-modular-atx-power-supply-500-watt-80-plus-bronze-certified-modular-psu

 

[RobCrezz]

Have you moved your monitor input to the gtx 660?

 

[Moose2_45]

I use my to as my monitor? Would that make any difference?

 

[Moose2_45]

Tv**

 

[RobCrezz]

No, just needs to be plugged into the graphics card (gtx 660), not the motherboard (integrated graphics ).

 

[Moose2_45]

Yeah I've done that and it still doesn't do anything. Just come up blank

 

[RobCrezz]

Do you have a monitor to test it with? sometimes TVs are not very tolerant to what resolution they will accept.

 

[Moose2_45]

No I don't. I didn't actually realise if I'm honest.