If you do not need the existing program and simply want to reuse the hardware, you can perform a factory reset. WinProladder Utility: Use the "Clear PLC" function within the WinProladder software
Technically, older firmware versions of the FBs series had vulnerabilities that allowed for "brute force" attacks or memory exploits. Various third-party software tools and scripts claim to "crack" these passwords by intercepting the communication between the PLC and the PC. Fatek Plc Password Crack