Extract the files from the zip and put both the FLASHIT.EXE and the BIOS file in the root directory of the memory key.
Rename the BIOS file to ZG5IA32.FD and then remove the disk.
Turn the AA1 off, insert the battery and connect the AC adapter.
Insert the USB Memory Key into one of the USB port of the Aspire One.
Press Fn+Esc, keep it pressed and press the power button to turn the AA1 on.
Release Fn+Esc after a few seconds, the power button will be blinking.
Press the power button once. The AA1 will start the BIOS flash, do not interrupt for any reason. After some minutes the power button will stop blinking, and then the AA1 will reboot. Wait till the AA1 has completed all this operations.