Can I add an Asus Radeon PCI-E X300 graphics card to a Dell C521? I've put it in the slot, but upon booting I get a message stating that the sytem is not configured correctly and I need a cable...I don't see any available cables to unplug from the board and plug into the card?? Any experience with this?
That card should work with your system. Try to reseat it and see what happens. Also keep in mind, that even if the card seems it should run with the system, not all cards are compatible with Dell systems.