If it’s not possible to change the FSB of your Celeron to higher frequencies than 66MHz you have to cover up pin B21 with a adhesive tape or nail varnish. Nail varnish have the advantage, because you can easily fit it over the hole pin and use nail varnish remover if you want to undo this. But that’s your choice… It’s easy to locate this pin – over these pins are some small numbers like B1, B73, B74, B121.
just count from the right Pin on the backside 21 steps to the left pin, but make sure you’re not on the A side !!!