Finger Board Replacement

Okay, the title says it all.

I have acquired a older dulcimer (probably from a kit). It looks pretty good and sounds quite good except...

there is a slight "thunking" sound on the first three frets. I have already raised the nut, I could raise the bridge, but I am already getting to the point where the action is a little high, still playable, but I'm not really wanting to raise it still more.

I have checked with a straight edge and indeed the fret board does curve slightly downward at the first three frets. So as far as I can see, I can pry the frets up to level them with the others, or I can replace the fret board entirely.

So the question: has anyone attempted to replace a fret board? How likely is it to ruin the instrument taking it off? Should I just forget it and live with the slight "thunking" at those frets (you can still hear the notes, they just don't ring out as clear)?

Any thoughts or advice?