Gigbyte ati radeon hd 4650 broken bios

hi i have a problem with my vga. when i have a clean windows install i cant install the catalyst drivers becasue they dont see the graphick card...
i mean in the selection screen is only catalyst and something else but there are no driver ect.
i used radeon bios editor and winatiflash i can only dump the bios but i can not flash the card... in the rbe is a vendor id and vga name section there is only vendor "gigabyte" bot no vga name its empty...
when i try to use winatiflash then widows crashes... in dos when i use flashrom or else there is an error that there is no graphic card in the system so i cant flash it... what to do?
sorry for my english...