After switching off the aa1, when trying to turn it on again, it just shows blinking leds and the fan is turning. But the screen remains black.

If your aa1 does like this probably its BIOS has been damaged…

Please note that the process I’m about to describe is only meant for emergencies and may void your warranty, so use at your own risk.

1) Format a USB memory key with the FAT mode.
2) Download the latest version of the BIOS from Acer support website.
3) Extract the files from the zip and put both the FLASHIT.EXE and the BIOS file in the root directory of the memory key.
4) Rename the BIOS file to ZG5IA32.FD and then remove the disk.
5) Turn the AA1 off, insert the battery and connect the AC adapter.
6) Insert the USB Memory Key into one of the USB port of the Aspire One.
7) 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.
9) 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.

If everything has gone right, the BIOS is flashed and all settings are reset to default.
http://apevere[dot]blogspot[dot]com/2009/01/acer-aspire-one-black-screen.html

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