Graphics card installation problems

I have an Optiplex 320 and I am trying to install a Radeon 4350 graphics card.  The computer took forever to boot and when it did, it would not allow me to install the drivers.  When trying again, the computer blue screened.  Before installing this card, I tried a GeForce card first and had the same problem.  It was suggested that since the onboard video was a Radeon, it might be better to use the same brand to avoid a conflict.  Neither worked.  What should I do?