Can you expand what you mean? the vertex shader is for graphics programmers to use and is on the card which can't be download. Are you talking about Pixel shader? Which is also already on your card and can't be downloaded The only thing that you can download on and for you graphics card is the 'Drivers'.
"90% of what is considered "impossible" is, in fact, possible. The other 10% will become possible with the passage of time & technology." -Hideo Kojima