This will only work if you have access to another computer and both computers can connect to the internet. Try taking the new card out and using your onboard graphics to load up xp/vista whatever on the first computer. Set up an account with www.logmein.com
and add the first computer to your account. Then log in to the account on another seperate second computer. Put the graphics card in your first computer and boot up. Go to the second computer and connect to the first computer (using logmein.com), then change the display settings, until the desktop appears on the first computer.