Hi i need help fast

with a error i got after making a thing in bios on my other computer.
I tryed to overclock my computer cpu in bios and i worked 10% overclock and it gave me 300mhz

so then i tried 30% and now my computer isnt working

, i get a message when starting the computer saying this:
"""""""""""""""""""
RADEON X700 SERIES
Bad BIOS checksum. Starting BIOS Recovery...
Checking for floppy...
Floppy not found!
Checking for CD-ROM...
CD-ROM found.
Reading file "P4P800-E.ROM". Completed.
Start Erasing...-
Start programing...\
Please turn of your system and power on again to get system back.
""""""""""""""""""""
all that text appears on the screen and it say it do a erasing and programing but when i power of and restart computer same error appear on the screen saying same thing... i have even try by manual to create a floppy to flash with the newest bios update but it dont work, i tryed before putting of the bios battery and i moved to clear CMOS , even that isnt working

i have tryed with another ati grafic card with no good resultat, taking of and on cpu and nothing happend, anyone know how to fix it =/ or i my Bios dead so i need to go buy a new motherboard
//Robin Sweden (Thx to all people coming with verry good information how to fix bios corrupt.
Btw excuse me for bad english and for long text, you now, im swedish
