Although I assume most of you probably know that updating your bios is dangerous, I'd like to add one more bios horrorstory... (with a happy ending, luckily)
First, the background story...
Over the past few months, I've been having problems with my harddisk speed. Just after start-up, the harddisks work perfectly. I can easily download, unpack files and play music at the same time. But after running for a few days the system becomes sluggish. My music skips and stutters, transfer speeds are low, etc. After a reboot, everything works fine again. In the past, I didn't have these problems; I could easily keep the system running for weeks on end, without any hickups.
(FYI, these problems could be caused by Windows, which slows down the harddisk speeds when it gets too many write/read errors.)
Now for the bios bit...
Yesterday, I checked out the website of my motherboard manufacturer (Gigabyte), and discovered a new bios version for my board, the EP35-DS4. I currently have bios version F3, and they had version F5. The release notes mentioned something about it fixing raid errors. I'm running my harddisks as ACPI, which uses the RAID controller. So I figured that might solve my problems. It was worth a shot anyway. After all, the board has dualbios, which should protect me if things go bad.
I downloaded Gigabyte's @bios tool, which can update the bios while running Windows. A lot of people say you shouldn't use Windows tools, but I've had good experiences using Asus' Windows tool.
I used the tool to update my system to bios version F5, and rebooted. Everything seemed fine bios-wise. Because it was reset to factory-default settings, I changed some things in order for my system to work (boot order and such). I restarted the computer, to start Windows... but all I got was a screen telling me an important system file had changed, and that Windows couldn't start.
After fooling around with various bios settings, I gave up. I simply couldn't start Windows anymore. I also couldn't use the Windows Vista DVD to repair the system. I didn't want to format one of the disks to re-install Windows, because I had no complete backup. I decided to re-install the older F3 bios. This time I used the update utility build into the bios itself.
During this second bios "update", everything seemed to go fine again. The utility reported that the update was succesful. Afterwards, I rebooted the system. But now my troubles started: the PC started up, then shut down again, over and over again. I didn't get any output on my monitor, no bios screens, nothing. I just had a constantly rebooting computer. One can imagine my frustration and fear...
After looking around on the internet (using an olde backup PC), I tried various things to fix the system. I cleared the CMOS repeatedly, I removed all non-essential hardware, I even tried poking around the bios chip with a screwdriver. Various websites said that you're supposed to connect two connectors of the primary bios chip. That will make the motherboard think the bios is corrupt. It will then install the backup bios in the secondary bios chip. But no matter what I did, the system kept rebooting.
Today, I was about to order a new motherboard for my system. But I wanted to give the thing one more try. I again tried poking the bios chip with a screwdriver. This time something different happened. The system rebooted again, but then didn't shut down; it stayed on. I rebooted, the same thing happened. So I shut it down, installed the rest of the system, started it again... and I saw a bios coming up. The system reported: "The bios is corrupt, reinstalling from backup" (or something like that). After recovering the bios, it rebooted again. When it came up again, I was looking at a working bios (version F1), from the secondary bios chip.
After that, I succesfully reinstalled bios version F3. And after tweaking that, I could start Windows without any trouble.
So... in case you were thinking about updating that bios of yours... stop and think: do you *really* need it?
I was very lucky I could get my system going again. I certainly won't try updating the bios again.