First time flashing BIOS for AV8 board

Have you checked the BIOS to make sure the RAID is turned off? I'd also clear the CMOS

I went into the option that asks if I want the SATA RAID to initialize during POST, it was on 'enabled'. I switched it to 'disabled' and still nothing. I doesn't ask about the RAID config anymore, but I still cannot boot from my hard drives. The BIOS still shows nothing. All that is showing are the two IDE DVD burners and not the SATA drives.

Make sure the BIOS is set up to recognize SATA drives as well as ATA drives. Check that the plugs on the SATA drive are secure. Make sure you have the SATA drive plugged into the correct connector, some boards have a set for RAID and a second set for non RAID. Also make sure it's plugged into SATA connector 1

There are only two SATA plugs, no separate ones for RAID. My BIOS is setup it recognize SATA and ATA drives and the plugs themselves are fine.

Have you tried a different cable? It's possible you have to reinstall the SATA drivers. At the beginning of installing XP it says if you have to install drivers or something like that hit the F6 key and at some point it will ask you to install them. Not sure if it works the same way during repair. The other thing you could try is the diagnostic/repair software from WD, running it off a floppy,

I've tried different cables and I've reinstalled the SATA drivers. Here's what I've done so far:

Installed an IDE hard drive and installed XP on that.

Installed the SATA drivers, now the two SATA drives show up as secondary drives in addition to the IDE drive.

I am able to access the files that are on the SATA drives, but what I want to do is use the system the way I did before, meaning I want to boot from the SATA drives. As of now, the system won't boot from the SATA drives.

If XP is installed on the ATA drive, this will be your boot drive. It doesn't sound like you have XP installed on either of the SATA drives. If you want to boot the SATA, you'll have to install an OS on it

The OS is installed on the drives. I've been using this system for two years now. When I decided to upgrade the processor, my mobo required an upgraded BIOS. Immediately following the update, my system no longer recognizes the SATA drives.

Do you have the BIOS set up so that the SATA with Windows on it is the first boot device? Want to make sure I'm clear on what is going on right now. You have Windows installed on an ATA as well as a SATA drive. Windows starts up but it's starting off the ATA drive. Once in Windows you can see all the drives and you can access all 3 of them.

The thing is, the SATA drives don't appear at all in the BIOS. Originally, I had two SATA drives installed; one with Windows XP and the other as a secondary drive. When I flashed and upgraded the BIOS, neither drive was being picked up by the system.

To make sure nothing on those SATA drives was deleted, I installed an ATA drive and loaded Windows onto that one. Once that was done, I was able to, from the 'My Computer' menu in Windows, see the two SATA drives.

Unfortunately, that is not how I want my PC set up, since the ATA drive is temporarily taking the space of a secondary DVD Burner that I need. I need my PC to be able to boot from the SATA drives as it once was able to do. For some reason, when I go into the BIOS and select which drive I want to boot from, neither of the SATA drives show up (but they used to).

How are your jumpers set up on your harddrives?

I haven't changed them since I originally set the system up two years ago. There are also no markings on the drives that tell which is 'master', 'slave', etc.

Hey buddy I once had this issue and got it fixed.

Just to quote you:
For some reason, when I go into the BIOS and select which drive I want to boot from, neither of the SATA drives show up..

When you are at the exact place in the BIOS to configure this option, the 2nd option under it, open it and this is where you can remove or add devices to boot from. Manually add your SATA drives (might have to remove the ATA boot from it which is harmless.

I have this computer in my closet and could take picture of the Screens in the bios. Sorry if my message is not too clear as this is not my main language.

I think you should backtrack here. You've made just two changes, the CPU and the Bios. let us assume for now that the CPU can't be directly responsible for controlling the Hard drives, HOWEVER the bios most definitely IS critical to how the hard drives are managed. Thus the problem must be Bios or its program. I would try to flash to an older verson of the Bios, the oldest that still supports the EM64 or whatever the upgraded CPU is (I wish you'd specifically listed the two CPUs) I have had a similar issue where video would not work properly after a bios flash due to resource assignment, using a different bios solved the issue. And that's another point, a completely new bios, one a couple years newer, will handle motherboard memory management differently. Hard drives can disappear due to resource conflicts, try removing all plugin cards, soundcard, Ethernet etc, and see if the drives are recognized on next boot.

The processor I originally had was an AMD Athlon 64 3400+. The one I upgraded to is an AMD Athlon X2 4200. The version of the BIOS that came with my system was ver.17, I flashed to ver.22, but ver.21 is the one that originally supports dual-core CPU's., so I'll try and flash to that one.

OK, I've loaded an earlier version of the BIOS onto a floppy and followed the instructions on Abit's site on how to flash (same as I did the first time).

I loaded the floppy, copied the files, and restarted the computer. I went into the BIOS and set the floppy as the first boot source, then restarted again.

The floppy loaded, then I get a message like, "REMOVE ALL DISKS AND MEDIA. PRESS ANY KEY TO RESTART"

I follow that, then the system restarts. I go into the BIOS and check the version. The BIOS hasn't changed. I repeat the steps, but this time I don't remove the disk and I hit any key to restart. The same "REMOVE ALL DISKS AND MEDIA. PRESS ANY KEY TO RESTART" message keeps appearing.

***UPDATE***

I was able to flash to 2 older versions of the BIOS. Ver.21 (which is the update that originally supported dual-core CPU's), but still I was not able to boot from my SATA drives. I then went back to the version that came with the mobo, Ver.17, still, nothing.