You'll have to go to your laptop manufacturer's website and see if there is a newer BIOS available...first. You'll have to put the old CPU back in to get the computer to a usable state (and to find out what the current BIOS is...).
Be sure the BIOS is 'exactly' the one for your laptop... there is the danger of bricking it if there is a failure or the BIOS is the wrong one! I haven't had one fail yet, but its always a possibility.
Instructions should be at the manufacturers website... but its either a Windows based update... or a DOS based update. If its Windows based... you basically just run the executable and it'll do the rest. If its DOS based, you'll need some way to boot to a CD/DVD, or USB floppy/CD/flash and run the BIOS update. Either way, after a successful erase/flash sequence, the system will reboot. Its often suggested to enter BIOS (often hitting ESC, DEL, F2, or F10 just after turning it on) and reset the configuration to defaults, but this may not be necessary. You'd need to put any non-default settings back if you did default them.
If the BIOS update did support more (particularly your new) processors, it should start working for you. The manufacturer might tell you what the BIOS update includes. Good luck!