Usually after i start the pc,it shows me the Asus mobo logo then i have to press F2 to continue to windows, now something is changed. I can't access the bios anymore, the screen is completely black until it gets to windows and the beep sound has changed. I tried removing the CMOS battery attempting to reset the bios but it didnt worked.Please help me, i can't install windows !!! (motherboard: ASUS m4n78)