Asus compatibility with ATI 9550

[specs1832]

I just built a new system with asus a8v deluxe, amd 3700, 1 gig of corsair ram, 200 gig hd, dvd-burner, dvd drive, ati 9550 graphics card, when i go to start it up, i get no signal to my moniter, i've gone over all my connections, and the ati box says it's compatible with amd athlon, i have no idea

 

[specs1832]

also, i used my old hard drives, do i need to reformat them to get rid of the old info, or no, my old cpu was an intel pentium 4, not sure if that would interfere