BIOS Blues

Lately I feel like I've been cursed when it comes to roll-your-own computers. My nicer machine went dead a couple of months back. Today, I reboot my Ubuntu system to find it will no longer boot-up. What the hell? Why does this keep happening to me? The box surviving POST, hung when it was supposed to launch GRUB. After some analysis, it turns out that if I unplug my SATA hard-drive, all is well. Anyway, to cut a long story short, after a couple of hours of trying to find a way to boot my system with the SATA hard-drive connected so that I could low-level format it (thankfully, I do keep backups), I figured out that if I don't plug the keyboard into the PS/2 socket but rather the USB socket, my system boots up with the SATA drive - no problems. Holy cow, this box is temperamental. A little while later I discover there is a newer BIOS for my motherboard that's still in beta (and has been for the last three years). After flashing the mobo I'm now able to boot up with my keyboard in any of the two sockets. To think I was this close to thinking my SATA drive was a brick. I also learned that my Athlon 900 should fit into my mobo that died a few months back - I wonder if I can bring that back from the dead?