HTML Converter v2.0 can't remember my license key

I have bought html converter and in spite of putting the key, I am not able to remove the red watermarks in pdf. What do I do to remove the watermarks?
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Please use administrator right to run HTML Converter v2.0 and input your license key, HTML Converter v2.0 will remember your license key forever, then it will not put the demo watermark to output PDF file, please to try.

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