How to reset bios password acer aspire 4315 without removing d cmos battery? I ever try to use default password for bios phoenix, but useless. so please help me coz I want to reinstal windows, change it from vista become xp, or Change setting bios to be Fist boot device is cd?

Resetting the CMOS password on an Acer Aspire laptop is much more difficult than resetting the password on a desktop.
Disassembly steps vary from model to model, but on most models, you'll have to take apart the computer to access the CMOS battery.
Don't take apart the notebook if you don't have experience disassembling PCs.
After turning off the computer and disconnecting the AC adapter, take out the battery (different from the CMOS battery).
All visible screws must then be removed from the bottom of the notebook.
Remove all components stored to their separate compartments on the base of the notebook.
Turn over and open the PC. Lift up the switch cover and remove the screws securing the keyboard to the PC, if any are visible.
Remove the keyboard.
Remove the screws securing the monitor to the hinges, and then set the monitor aside.
Disconnect all visible cables connected to the motherboard; and then remove the screws from the top cover.
Remove the top cover to reveal the motherboard. Locate and then remove the CMOS battery. Leave it out of the notebook for 24 hours; then reinstall it and reassemble the Acer Aspire.
Other Options
If removing the CMOS battery fails to clear the password, or if you dont feel comfortable with the idea of opening your computer, you might be able to gain access to the computer using a backdoor password.
These special passwords were implemented to allow technicians to access locked computers. Not all models recognize backdoor passwords.
Most Acer Aspires use the Phoenix BIOS, and backdoor passwords for this BIOS include BIOS, CMOS, phoenix and PHOENIX.
All of these passwords are case-sensitive.

Is it an aspire ?
Resetting the CMOS password on an Acer Aspire laptop is much more difficult than resetting the password on a desktop.
Disassembly steps vary from model to model, but on most models, you'll have to take apart the computer to access the CMOS battery.
Don't take apart the notebook if you don't have experience disassembling PCs.
After turning off the computer and disconnecting the AC adapter, take out the battery (different from the CMOS battery).
All visible screws must then be removed from the bottom of the notebook.
Remove all components stored to their separate compartments on the base of the notebook.
Turn over and open the PC. Lift up the switch cover and remove the screws securing the keyboard to the PC, if any are visible.
Remove the keyboard.
Remove the screws securing the monitor to the hinges, and then set the monitor aside.
Disconnect all visible cables connected to the motherboard; and then remove the screws from the top cover.
Remove the top cover to reveal the motherboard. Locate and then remove the CMOS battery. Leave it out of the notebook for 24 hours; then reinstall it and reassemble the Acer Aspire.
Other Options
If removing the CMOS battery fails to clear the password, or if you dont feel comfortable with the idea of opening your computer, you might be able to gain access to the computer using a backdoor password.
These special passwords were implemented to allow technicians to access locked computers. Not all models recognize backdoor passwords.
Most Acer Aspires use the Phoenix BIOS, and backdoor passwords for this BIOS include BIOS, CMOS, phoenix and PHOENIX.
All of these passwords are case-sensitive.

Step 1:
The Acer Aspire stores the password in a component called the complementary metal-oxide semiconductor. This component is integrated into a random access memory chip embedded on the motherboard. The CMOS holds data that the basic input/output system - a critical software utility that controls how the computer operates at startup - accesses when the computer boots. If the BIOS detects that a password is registered in the CMOS, it will prevent the computer from booting until the user enters the password correctly. Depending on which model of Acer Aspire you own, you may be able to clear the CMOS manually. Contact Acer before attempting to clear the CMOS, as opening the computer without permission could void your warranty. Desktop Models Some Acer Aspire desktop models come with a jumper that is used to clear the password and other settings stored on the CMOS. This jumper is located on the motherboard and is often found next to a label such as "JBIOS1" or "CLR_CMOS." To clear the CMOS using the jumpers, turn off the computer, disconnect the power cable and remove the case cover. Remove the jumper shunt from pin 1 and pin 2; then place the shunt on pin 2 and pin 3. Return the shunt to its initial position after 10 to 15 seconds. If the Aspire doesn't come with a jumper to reset the CMOS, the CMOS can be reset by removing the lithium coin-cell battery instead. Removal is accomplished by pushing down on the tab securing the battery to the motherboard and lifting the battery out of its slot. Leave the battery out for 24 hours, and then return it to its original position with the positive sign facing up. Laptop Models b> Resetting the CMOS password on an Acer Aspire laptop is much more difficult than resetting the password on a desktop. Disassembly steps vary from model to model, but on most models, you'll have to take apart the computer to access the CMOS battery. Don't take apart the notebook if you don't have experience disassembling PCs. After turning off the computer and disconnecting the AC adapter, take out the battery (different from the CMOS battery). All visible screws must then be removed from the bottom of the notebook. Remove all components stored to their separate compartments on the base of the notebook. Turn over and open the PC. Lift up the switch cover and remove the screws securing the keyboard to the PC, if any are visible. Remove the keyboard. Remove the screws securing the monitor to the hinges, and then set the monitor aside. Disconnect all visible cables connected to the motherboard; and then remove the screws from the top cover. Remove the top cover to reveal the motherboard. Locate and then remove the CMOS battery. Leave it out of the notebook for 24 hours; then reinstall it and reassemble the Acer Aspire. Other Options b> If removing the CMOS battery fails to clear the password, or if you don't feel comfortable with the idea of opening your computer, you might be able to gain access to the computer using a backdoor password. These special passwords were implemented to allow technicians to access locked computers. Not all models recognize backdoor passwords. Most Acer Aspires use the Phoenix BIOS, and backdoor passwords for this BIOS include "BIOS," "CMOS," "phoenix" and "PHOENIX." All of these passwords are case-sensitive.

plug off your bios battery, and plug in again it can reset your bios password

What you need to do is Flash the BIOS.

http://support.acer-euro.com/drivers/notebook/as_4315.html

With this utility you should be able to FLASH BIOS to factory default and enter BIOS without password. Be extremely careful to follow the steps exactly, because one false move and your system could be rendered useless.

Hope this helps

remove cmos battery either notebook battery for 5 minutes. Connect the 2 pins for few seconds (NOT the battery), put them back and let's try....

The password to by-pass bios password are these, hope they will hope you, once you enter BIOS using these passwords you can reset it to normal
Phoenix Backdoor BIOS Passwords:

• BIOS
• CMOS
• phoenix
• PHOENIX

to reset bios password just take out the cmos battery and reinstall

This is the only way to do it.
http://www.cgsecurity.org/wiki/CmosPwd


Please rate this fixya solution

Ok.. Seems like its the HDD password set using the BIOS. You can remove this pasword by taking out the CMOS battery for about a minute. This would reset all of your BIOS settings to default there by clearing the password. For more information click here