2 Graphic cards

Hi guys, I am wondering if i could use 2 graphic cards in my PC. My system specs are : Emachine T4480 2.4 GHz 1 gb ram 2 HD's my orignal graphic card was a ATI 9000 radeon 64mb. Now i have a ATI 9550 as my main card in my AGP slot.
My second card i had laying around is a ATI readon not sure on the series probley 7000 (PCI). when i put the PCI card in i reboot my machine i get both monters with black screens. i was reading somplace that the cards are fighting for witch one is the main card. there has to be some way to get these cards to run.
If there's any thing i left out please excuse me

 

Whats ya try to do Snake? dual monitors?
Ya might check your BIOS & see what your options are for graphics, if there is an auto setting try that. ( I'm thinking your options are Pci/AGP or Auto)
I doubt youll be able to run both cards at the same time.
If you can only run one your AGP is the best.