Hi BC ... well tried to enable that by holding the left shift then typed into notepad then tried right shift held for about 12 seconds and then typed to notepad and then held both shifts for 12 seconds and still no lock to keyboard.. Decided to hold longer than 8 seconds so that if its a function of the laptop it would trigger and lock out keystrokes.
One detail I forgot to mention is that its running Windows 7 32-bit on 2GB RAM if the OS matters for support of the FilterKeys function.
It shipped initially with Vista and the prior owner upgraded it to Windows 7 32-bit before throwing it away because it no longer powered up. I was given the computer because it was going to cost him $20 to get id of it and I said I can dispose of it for you for free. He gave me it and I troubleshot the issue to a faulty power cord. Chopped the end off of a HP power supply that no longer had a laptop associated with it from another laptop that I scrapped for parts and added this Gateway plug end to the HP power supply with proper polarity same voltage and amp rating and the laptop came to life. Was going to give it back to him but he said I can keep it because he already bought a new laptop. So this laptop replaced my around the home and on the road clunker laptop that if it gets broken or stolen no big loss.
If the cat was sprawled out across my pricey Core i5 laptop I would have freaked out. Its sort of like having a clunker car that works and if it has a cat on it no problem no yelling just move the cat nicely, but with a brand new car I'd be freaking out that the cat is going to damage its paint etc.