It's impossible to speculate without seeing it but if you mean that the neck is bowed it could be a trussrod problem, since it seems that you have no dovetail joint. I wouldn't plane off the old fretboard if it can be salvaged. Usually the fretboard can be lifted off with heat and gentle prying. If the trussrod is good, necks can sometimes be straightened by applying heat and clamping the neck using a pivot point to bend it in the opposite direction. When the neck cools it should hold it's shape. I wouldn't try this without accepting that there are risks of other damage. If however, it's home repair or the fireplace, it should be worth a shot. If there is a skew lenthwise in the neck the heat and clamp method will also work but it is more difficult. Be sure to leave a bit of bow in the neck or your strings will buzz. Sometimes minor twists and squews can be fixed by replacing some frets with higher ones and then filing them in line with the strings. If nothing else is gained but knowledge from trying different things it would never be a total loss.
Best of luck!