The name of the chemical escapes me, but there is a stripper made for just this problem. It will remove most if not all the stuff, but will stain the surface of the wood.
Sanding is useless as the stuff gums up too fast and makes sanding a joke. You have to dilute and remove the stuff first.
Then second comes the refinishing process.
This might become too much of a project and you might consider giving up and installing 1/4 inch plywood screwed down and install new flooring of some sort.
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