Do you use Loader ? I modified your bios with HP 2.1 Slic, but you have shown Asus 2.1 Slic. Remove any Loaders and check again.
The BIOS File is named: p55us3l2.fh Make a Bootable USB Drive and copy the files from the Rar archive to that Bootable USB and re-boot with USB Drive set as Firts Boot Device in Bios Settings. Then the autoexec.bat wil auto flash the Bios.
Sorry for the confusions, here is what I did, step by step: 1. I flashed your modified bios with HP SLIC and SLP, with windows xp installed, no success. 2. I downloaded the AMI SLIC Mod 1.61 tool, modified the original BIOS with HP SLIC and SLP, the resulting BIOS file was exactly the same as your BIOS file 3. Used AMI SLIC Mod 1.61 tool, modified the original BIOS with ASUS SLIC and SLP, and flashed this BIOS, this is the current BIOS in the motherboard. Still no success with Windows XP. 4. For testing, installed Windows 7, and installed certificate for ASUS, SUCCESS with Windows 7. 5. Posted the screens you requested, as you can see the SLP tab shows No OEM SLP found. I am trying to get Windows XP to work, as that is what I want to install. Thanks