Is it true that removing the battery will clear the passwords?
It can clear BIOS passwords if you leave it out long enough. It won't however clear passwords present on the operating system.
Battery is the best method ive seen but there have been instances where in old computers the cmos can prevent the battery from overriding the bios password.
but there a few ways
removing the battery works on most of the new systems because most of them dont have jumpers
jumpers are like the main method for removing the bios password on some old computers because on how they were built they had batteries and jumpers.
backdoor passwords are on all bios for the manufacters so they can gain access easly and quickly if they need to.
there are more ways but theses are the normal ways
How about windows passwords?
clrcmos for clearing out cmos passwords
How to use
Boot to DOS. (using a bootable floppy or CD containing CLRCMOS).
Type clrcmos on the command line and press enter
Works on 99 % of computers
Method 2 can be done in Safe mode too