I need to DEGRADE my BIOS on C840

Interesting that you are having this problem the very day that I am googling it. I am also having this exact issue. How do we downgrade the bios?

Well I got the Bios to Degrade to version A12 instead. However this Bios Version seems to have the same issue as A13 with the freezing.

I will try to find a different version of the FlashBIOS Disk.

Dell Computer Corporation
Copyright (C) 1999, All Rights reserved.
www.dell.com

BIOS Downgrade Instructions
===========================

Dell FlashBIOS diskettes include the file UPGRADE.EXE. UPGRADE.EXE checks
the existing FlashBIOS installed on the system, and makes a determination
whether or not the FlashBIOS on the diskette needs to be installed onto
the system to *UPGRADE* the system FlashBIOS to the latest version. If the
FlashBIOS contained on the disk is older than the FlashBIOS installed on
the system, UPGRADE.EXE will simply return the message "BIOS upgrade is
done!" (without performing a flash), and terminate the failed upgrade at
an A:\ prompt.

To view the content of the diskette and determine the name of the FlashBIOS
file, type DIR at the A:\ prompt and press the key. The FlashBIOS
files will contain a .EXE extension.

For example:

LCP_A07.EXE    Latitude CP
LCPi_A04.EXE     Latitude CPi
CPIA-A00.EXE     Latitude CPi A
CPCR-A00.EXE     Latitude CPt C / CPi R

To downgrade the FlashBIOS at this point, simply type in the name of the
FlashBIOS you want to install at the A:\ prompt and press the key.
Follow the onscreen prompts that appear on the screen.

* End *

After Way too long figuring my way through things, I got it to work. I used a Virtual Floppy Drive to extract A03 from the Installation file on dell.com. then added it to a bootable CD with DOS. Then slowly got the Process to install A03 Bios... which seem to have issues of their own, but at least it boots into windows.