I've only ever seen that happen when sugary drink / coffee has been spilt on the keyboard - think the membrane inside had been short-circuited in some way which resulted in similar problem to yours appearing.
It is my computer at home. This is my work computer!
I've tried putting number lock off - that doesn't make any difference on this computer.
Doglady, if J,K,L comes after H then they are in the right places!!!!!!!!