My dad installed my hardwood floating floor - it's one of those tongue and groove systems which he glued together. He didn't do it correctly and now it moves around and generally isn't right.

He also used less than half as much glue as he was supposed to when he glued it together.

Is it possible to pull it up and start again, using some or all of the same floorboards? Or do I need to just start all over again with new boards?

I've seen it done once, but you'll have to run it through a mill shop to clean all the dried glue out from the tongue and groove so it fits proper again. It may also depend if some glue got on the surface, as it could pull splinters from it. Personally I think it's more trouble than it's worth.

Magnum Tools has that "skimmer" tool for cleaning T&G's, when doing repairs.

It would be a chore to re skim a floor, but not impossile.

You may bust off some T&G's trying to get it apart in the places it did hold.

I'd live with it. The cure may be worse than the illness.