If you take an oath on the Bible but don’t believe in it, does it count?

The whole point of swearing on the bible was to get God to be involved in enforcing the oath. So your disbelief may negate this aspect. On the gripping hand, you also swear in front of a government representative to get the gubmint involved in enforcing the oath. And if it is in their interest to enforce the oath; they will. With guns if necessary.