I bought a house 5 years ago and now my neighbors want to put up a fence. The driveway that is between the houses has been there for almost 50 years is over the line by 3-4 feet. Doesn't the driveway become the property line. Also the fence on the other end of the property is about a foot over, It has been there for 10 plus years and is a metal fence.

It does not automatically become your property, you will have to file in court for ownership though adverse prossession of the property.
I would get an attorney.

But the land is still thiers unto you do that. ** did you not get a land survey done before you bought the property?