The is elusive because it was never meant to be sold separately. However, with the Veriton M275 Service Guide and the information provided in this article, you have everything you need to install, upgrade, troubleshoot, and repair this vintage board.
The Acer G41M07 motherboard uses an Award BIOS. To enter the BIOS setup, press the F2 key during boot-up. acer g41m07 motherboard manual