Hi !. Gigabte X58A-UD3R. I had a similar problem . I solved it by updating the bios. In my case my computer booted perfectly but when creating a raid 1 (with DSM) dsm modified the MBR of the new hard drive. The next time the computer would not start and stayed locked in the bios. When removing the new hard drive, the computer booted perfectly again. I updated the bios and I solved the problem.