Today I've had a case with an Acer Aspire 1350 which had his bios locked with a password and I couldn't boot from a cd to install windows because the boot up menu was set up to boot from hard disk first. I've tried to remove its hdd and then connect it to a different pc, install windows on it and then put it back on the laptop, but that did not work also, because of the windows protection. So after a little googling I've managed to find a code which can reset the bios password and unlock it. If you have a similar case with a locked bios and can't change the bios settings, here is what might work for you. It works with most of the old notebooks who has the same bios.
Here is the model that worked for me:
System Manufacturer: Acer Inc.
System Model: Aspire 1350
BIOS: PhoenixBIOS 4.0
If you can't boot from the cd, Remove the hard disk from the laptop and since there is no hdd available it should boot from the cd(because the boot order in the bios is set to boot from cd if there is no hard disk)
Boot your pc in MS-DOS mode. A bootable diskette might also work, but if you don't have floppy drive, you might try with a bootable win98 or make a bootable cd with dos, just google it, you should manage to solve this)
After you get to the c:\> or c:\WINDOWS> prompt type DEBUG and then press Enter.
A hyphen(-) prompt will come up waiting for you to enter commands.
Enter the following commands, pressing Enter after each one. (Note: the o is the letter o and stands for OUTPUT).
o 70 2e
o 71 ff
After the q command type exit.
Restart the computer and check to see if you can enter in the bios and change the values like it should.