ibm pcl 300

Replace the CMOS battery. If you still get the "System Security -keyboard is locked" error after that, check the security level jumper on the motherboard. (I don't remember the J-number, but there is a key on the inside of the case.)

If the security level is set to HIGH, the BIOS password is flashed into the BIOS and cannot be reset unless you know the password. IBM's recommendation in these cases has always been to replace the mainboard, as it is cheaper than replacing the BIOS chip.

I've found that removing the board sans board battery and all leads sometimes works wonders.

I assume, given my limited training in these matters that this removes the potential of any latent differencial between the capacity of the steel of the case and the dis-similar metals of the board. This can, in theory, act as a battery or even a simple capacitor and thus "create" enough charge to mess up a bios.

It seems to work, as silly as it may sound.