Rispondi a "Bad motherboard causing blackscreen "Operating System Not Found"?"My pavilion has the same problem. I hat the BOOTMGR error, so i reinstalled vista and it would not work. I had a new motherboard installed, and it did not work. BIOS reset did not work for me. Place the recovery disc, and press f10 on the boot screen. Change the BIOS to CD Rom and it fixed it. Hope this helps.