How to Update the BIOS in an ASUS P5Bby Oxana Fox ; Updated February 10, 2017
ASUS P5B is a socket 775 motherboard that supports the Core 2 Duo family of Intel processors. The basic input/output system, or BIOS, is a program code integrated into the motherboard chip. BIOS initializes all hardware when the computer starts. Older BIOS versions may not properly recognize a CPU model, reducing the functionality of your computer as a result. The ASUS P5B motherboard has a special utility, EZ Flash, that greatly simplifies BIOS updating, also known as flashing.
Formatting the USB Flash Drive
Insert a USB flash drive into the USB port on your computer.
Click "Start" in Windows, and then click "Computer" to start Windows Explorer.
Right-click the USB drive icon and choose "Format."
Select the option "FAT32" from the "File System" drop-down menu and click "Format." Then click "Yes" to start USB drive formatting.
Wait for a message that indicates formatting is complete.
Copying the Latest BIOS File to the USB Flash Drive
Use a web browser to navigate to the ASUS download page (see Resources).
Select "Motherboard" in the "Product" drop-down list, select "Socket 775" in the "Series" drop-down list and select "P5B" in the "Model" drop-down list. Click "Search."
Expand the "BIOS" category by clicking the plus sign to display the list of available BIOS versions for the P5B motherboard.
Find the latest BIOS version, which should be at the top of the list, and then click the "Download" link to save it on your computer. The BIOS file has the extension ".ROM."
Insert the formatted flash drive into a USB drive on your computer.
Click "Start" in Windows, and then click "Computer" to open Windows Explorer.
Use Windows Explorer to copy the BIOS file to the USB flash drive.
Insert the USB drive with the BIOS file into a USB port on the computer.
Restart your computer.
Press the keys "Alt" and "F2" simultaneously when the message "Press DEL to enter SETUP, Alt-F2 to enter EZ Flash utility " appears on the bottom of the screen to bring up the ASUS EZ Flash window.
Use the "Tab" key on the keyboard to select the USB flash drive.
Select the BIOS file on the USB drive and press "Enter" to start flashing the BIOS. After the process is complete, your computer will automatically restart.