It's my assumption that you are talking about on the inside of the house, below your bay window. No matter what you try, you haven't addressed the primary problem of dampness inside of the structure. This will, over time, cause serious problems. I would take a look at the outside and try to determine where the moisture is coming from. It could be damaged caulking around the outside of the window or it could be the neccessity of ventilating the area under the window. In that case, if you are reasonably handy, there are small, circular aluminum vents that could easily be installed to give the area some air circulation. At any rate, try to determine the base cause before applying any more cosmetic fixes, since they will be temporary, at best...