As both the POTHML and PPSX file type originate from Microsoft PowerPoint, it is probably the easiest way to use that program to simply re-save one to another.
Convert Microsoft PowerPoint HTML template file to Microsoft PowerPoint 2007/2010 Open XML complete slide show.
We found one software available in the database for this conversion.
Microsoft Windows software - convert pothtml to ppsx on Windows
A presentation program from the Microsoft Office suite
Convert from pothtml file format
|Yes, Microsoft PowerPoint supports ppsx file conversion as a target file type.||Yes||Yes||ppsx editor||Yes||No||No||No|
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.