EZ Bios Problem – A: drive not available

On my old Gateway Computer, I upgraded my Bios, but I had WD’s EZ Bios running. I goofed up and let the Bios Upgrade run incorrectly (without using the EZ Bios key sequence). Now, when I boot up, it says my Disk Controller (for my A: drive) is notworking. It was working before the Bios upgrade. Other than that it’s working decently (as I said, it’s an old PC). I’d like to reformat my machine and re-load windows, but can’t do it without the ability to use a boot disk. I’m running Win 98 SE. I tried to boot to a CD, but my Bios looks like it doesn’t have that option. What are my options at this point?