BIOS ROM checksum error fix

So I had an old HP computer (HP Pavilion Slimline s3023w) that I was using to make a web server, but I kept getting some annoying errors. I thought it'd be a good idea to update the BIOS. I found the webpage for my specific model on the HP website, and I downloaded the executable that supposedly was going to update the BIOS...but it ended up crashing when the computer was restarting, leaving me with the dreaded BIOS ROM checksum error. I couldn't even use the USB ports! The fixes online all included the use of a floppy disk, but I didn't have a floppy drive handy. But, my computer did have an optical drive and I was able to fix it with the following steps. Hopefully, this process will help you out if you have a similar problem.

0. Get a PS/2 keyboard if your USB ports don't work.

If in your case, as in mine, your USB ports don't work in this state, make sure you have a PS/2 or USB to PS/2 connector to connect your keyboard. You can't do anything if you can't type commands into the prompt.

1. Make sure you have a working optical drive and a blank CD or DVD

We're gonna emulate a floppy drive through your optical drive, so we need that optical drive!

2. Find your latest BIOS file from your manufacturer website. Extract .EXE if necessary

Find your motherboard/computer model and go to the manufacturer website and download the BIOS file. In some cases, the manufacturer will just have a .exe file. What you want to do in this case is extract the .exe file to open and view it's contents. (I used the Unarchiver program in Mac but there are many similar programs to do the same in Windows). This BIOS file will more than likely be a ".ROM" file. Extract it, save it somewhere, and rename it to something simple like "bios.rom". Do not change the extension name from anything other than .rom!!!

3. Download Awd Flash

This program will help your motherboard install the bios. Rename the.exe file to awdflash.exe
The download link is here.

4. Download CDBurnerXP

Link for download here.

5. Download UltraISO

Link for download here.

6. Download and Extract Ultimate Bios Boot Edition

Link for download here.

7.1 Create bootable CD

Install and open UltraISO. Now, in UltraISO, open the drdos.img file located in Ultimate Bios Boot Edition folder (located in folder boot_cd).
Now drag and drop awdflash.exe and your bios.rom file into the UltraISO window with the other files (COMMAND.COM, etc). Now save and exit out of UltraISO

7.2 Create bootable CD

Open CDBurnerXP and click Data Disk. In the "Disk" menu at the top, click it and select "Boot Options." Make sure to select "Make disk bootable. Now choose the boot image path to that of the drdos.img file you saved earlier. Select emulation to "floppy 2.88mb" and make sure your platform fits your computer. Click "OK"

Now, drag your drdos.img file along with your bios.rom file and awdflash.exe into the window and burn your disc using the burn button.

8. Insert disk and restart computer

Hopefully your computer will detect your disk. If so, the DOS prompt will show up showing A:>
You can type in the command "dir" to see the files. You should see your awdflash.exe file along with your bios.rom file.

9. Type in command awdflash [FILENAME] [/...]

Assuming your bios file is "bios.rom" and your awdflash executable is "awdflash.exe", run this command to update bios manually:
awdflash bios.rom /py /sn /cc /cd /cp /R
Let your computer do its thing and restart.

10. Done!

Remove the disk, and restart again. Your computer should be working now!

If everything went well your computer should no longer have BIOS ROM checksum error, and you will no longer have to toss your mobo out.