Ok I am a total noob when it comes to this, but still learning. I have a late 2004 G5 desktop running OS X 10.5.8. I just recently picked up a Mac Pro 3,1 but there was no video card present (brought off eBay). I googled and saw that I can use a non Apple video card. I went ahead and picked up an ATI Radeon HD 2600 while I wait for my Sapphire Radeon 4870 to get here. Anyways my problem is, is that I pulled the hard drive from my old system and tried putting it into my new system. When powered up I get nothing, but a black screen. What I need help with is how do I get my video card to work on the current OS I have installed. I am willing to format and install a new OS but how would I do that?