I'm planning on upgrading my aged HP Pavilion a6640a 's graphics card ( Currently a nvidia 8400) to a GTS 250 1gb. Can you guys please tell me if this is going to work or fail miserably. I know how to replace a graphics card, I've done it before but I haven't upgraded a HP Pavillion a6640a with a GTS 250 before . I just need to know, will it work? If it doesn't work, I'm willing to use another graphics card like a ATI 5750 1gb. I have a budget of around 150 dollars. Thanks guys...