To recover a forgotten password on an Acer laptop without losing data, various methods are available depending on the operating system. For Windows 8, users can utilize tools like the NT Password tool or third-party software such as Windows Password Genius Advanced, which allows password reset via a bootable USB or CD. If a password reset disk is available, it can be used to initiate the Password Reset Wizard. For older systems like Windows 7, accessing the built-in administrator account through Safe Mode may also provide a solution, assuming the account is not password protected. It's important to note that simply removing the internal battery may not work for Windows passwords, as this method typically only applies to BIOS passwords. If all else fails, reinstalling the operating system is an option, but it will erase all data.