Bios password for dell inspirion 6400

You are probably referring to the BIOS password. Call Dell Support to request the reset password. (800)624-9896

BIOS passwords are usually set by IT departments and are intended for system security.

There are only 2 ways to fix this.

Get the password if purchased legitimately or replace the system board for $300-400 from Dell. There is no other way to bypass.

Is it the BIOS password or Windows password you are trying to get past. You can remove the battery on the motherboard and leave it out for 24 hrs or more and it should clear the BIOS password. The battery is a small round one like in a watch and it keeps power to a chip so your system wont lose the date/time and BIOS information. If its the Windows password you will have to use the adminstrator options or reinstall Windows completely and setup new passwords, eMail me at [email protected] if you need more assistance.

Is there any clr cmos written on the board. The motherboards which do not have jumpers come with three point like solder on the board. You have to short first two manually with some wire.
If it is not there then you have to flush the bios with the bios flushing utility.

if you really cant find it you could try taking the cmos battery out for 40sec and then reseating it.
that would clear any bios passwords

open the case and remove the battery that is on the main board

After a lot of research and many attempts to unlock my Dell Laptop with biospassword, while talking to Dell Support, I finally found this website www.biosunlock.com

REMOVE THE CMOS BATTERY FROM THE MOTHERBOARD AND INSERT IT AGAIN TO RESET BIOS PASSWORD..

If you are not afraid to open the box, the simple fix would be to remove the cpu battery(looks like a quarter) for about 30 seconds and replace, then boot up. At that point it will ask for information such as date and time, but then you can access the bios

If you are the rightful owner dell will help you reset this.
but it will take some time.
or
you will have to remove the cmos battery (looks like a coin) under the keyboard and main battery
wait a few mins and try again.
if that does not work then only some techs knows what chip to short to clear.
like me.