If you use other software can be converted to PDF WORD format, that the PDF is not encrypted. Recommended the use of SolidDocument SolidConvertPDF software, this software should be converted out of the WORD file will basically keep the original source document style. There will be no watermark.
In addition, as for the watermark can not be removed from the problem may be due to the limitations of the converted file. Usually the watermark may sit in the background image or the header and footer, you can also look for it and remove the watermark.