The Dell Latitude 2120 is unique among netbooks because it retains an old-school on the motherboard, despite being a modern(-ish) device. This jumper, when shorted during boot, tells the BIOS to erase the password.
If the online generators don't work, you can get a master reset code from Dell Support. Contact Support : Reach out to Dell Technical Support Verification : You will need to provide your Service Tag dell latitude 2120 bios password reset