Comments by LilliamClifford (Top 4 by date)

You mentioned you cannot convert them to image, then how about converting your powerpoints to pdf in c#, with that you would be able to show the pdf file page by page in an iframe element from your html page.

Or you could between html and word in C# interchangeably and just use any WYSIWYG html editor on your page.

Here is how you can convert excel to pdf in c#, also here is how you can directly export that excel or pdf in asp.net.