There was this eSettings.exe which let you change some BIOS Settings from Windows, including the password. Of course it first asked for the old password and showed a prompt, denying the request if it was wrong.
I fired up good old OllyDbg and traced the prompt in the ASM code. I changed only one bit IIRC (jne to je, or similar), saved the .exe and tried my luck.
It let me through the prompt and I entered the new password. Amazingly the BIOS gladly accepted it!
I didn't bother to find out what functions it exactly called to set the new password to write a small tool, because I already had one. ;)
I wonder if this still works... If not with an Acer, maybe with some other make?