screwed up flashing bios! need help!!!!

hey i wanted to flash my bios from a 9800 pro 128mb to a 9800 xt 128mb. my pro is a core of 350 and i flashed it with the xt's core fo 360 so now i screwed up. all i have is a black screen on my computer and i didnt even back up the original bios. i dont have a pci vga card either.i do have other computers so if theres a file i can burn to a cd and if there is a way to boot the original bios up. i already burned the original bios from this sites bios directory to a cd, the .iso file and i put it into the computer but nothing happens. plese help me if u can give me a thorough explanation on what to do i would be eternally grateful. thank you!